What are your views on the choice of name for the new model? Please provide your reasoning and any supporting evidence.

We are satisfied with the choice of name.

What are your views on the choice of name for the version of the model which is to be used to demonstrate compliance with the Future Homes Standard? Please provide your reasoning and any supporting evidence.

We are satisfied with the choice of name for the FHS assessment version of the HEM. It makes sense to include specific reference to the FHS, as this makes it clear what the model’s application will be and distinguishes it from the underlying model.

What are your views on using the open-source code as the approved methodology for regulatory uses of the Home Energy Model? Please provide your reasoning and any supporting evidence.

The NIA welcomes the move to publish the open-source code, as this will aid transparency and promote greater understanding of the methodology among relevant stakeholders. It will also give industry experts the chance to scrutinise the code and suggest improvements or raise any potential concerns. This should improve the overall effectiveness of the model.

If the open-source code is used as the approved methodology for regulatory uses of the HEM, we would like to see more clarity and guidance on what the process will be for dealing with errors in the code, in particular around liability and the transfer of risk. If there are errors with the centralised code, it is important that risk and liability is not transferred onto individual software providers who use the code as a basis for producing EPCs and determining compliance with building regulations. It is also important to avoid a situation whereby errors in the code become embedded into law.

It is important that making the open-source code the legal basis for the methodology does not act as a barrier to making necessary changes to the model in a swift manner. It must be possible for the HEM to be constantly improved and refined to improve its effectiveness. There is the potential that a codebase underpinned by regulation will be very slow to change. It is important that this does not act as a barrier to regular updates and improvements to the model. As mentioned earlier, if there are errors in the code, it is vital that these are rectified as soon as possible, without the need for a long, drawn-out regulatory process.

Whilst we agree with publishing the open-source code, it is important that other documents are published alongside it so that people not familiar with Python are still able to understand the methodology behind the model. It is encouraging to see that the Government will be publishing accompanying technical documents to provide further explanation about the model. This will ensure that the methodology is accessible to a wider range of people, thus aligning with the Government’s objective to make the HEM more transparent.

What forms of collaboration would you be interested in for future development of the Home Energy Model codebase? Please provide further details.

There must be a clear process for managing, evaluating and updating the codebase. It is important that industry is involved in this process so that they can shape the future development of the codebase.

What are your views on our assessment of issues with the current SAP delivery model? Please provide your reasoning and any supporting evidence.

We agree with the issues outlined with the current delivery model, however it is unclear how the HEM will resolve all of these, in particular the inertia of the SAP methodology. If the codebase is embedded in regulation, this could complicate and slow down the process of making changes to the methodology. Introducing a centralised, cloud-based version of the code has the potential to enable quicker updates to the methodology. However, it is not entirely clear how this would operate in practice and what the relationship would be with accompanying regulations.

Lack of accountability is a key issue, however it is still unclear from the consultation proposals where the balance of accountability will lie with the HEM. We would welcome clarity on who will be accountable, whether this be the Government, BRE, or independent software providers. If the Government proceeds with a centralised, cloud-based version of the HEM, this could simplify the issue of accountability.

At the moment, different software providers all have differing versions of SAP which can cause inconsistencies in results, although these tend to be small. Having a centralised, standardised code should help to minimise these inconsistencies in results. It should also help to clarify the accountability of different parties by providing one consistent version of the ‘truth’.

What are your views on the concept of a centralised, cloud-based version of theHome Energy Model, to be used for regulatory purposes? Please provide your reasoning and any supporting evidence.

We agree with the concept of a centralised, cloud-based version of the HEM. Currently, different software providers have differing versions of SAP which can lead to inconsistencies in results. Centralising and standardising the model will help to increase accuracy and minimise these inconsistencies. The ability to make quick updates to the central platform is key.

It can be unclear where the balance of accountability lies with the current version of SAP, whereby different software providers implement differing versions of the methodology independently. Having a centralised, standardised model will help to clarify where accountability lies and transfer risk away from software providers. It is important that it is clear which body is ultimately responsible for the HEM (whether this be BRE or the Government).

The provider of the centralised model (BRE for example) will need to understand and put in place appropriate support arrangements to allow independent software providers to easily build user interfaces around the central platform.

What are your views on revising the database of product characteristics (currently the “PCDB”) for the Home Energy Model? Please provide your reasoning and any supporting evidence.

We agree with the intention to revise the database of product characteristics for the Home Energy Model. It is important that the PCDB is based on accurate and up-to-date data, and includes the most effective technologies currently on the market.

What changes would you recommend to the PCDB data collection procedures? Please provide your reasoning and any supporting evidence.

It is costly for manufacturers to get their products listed in the PCDB. This prohibitive cost means that many products are not listed on the database because it isn’t worth the effort and cost for manufacturers to apply for their products to be listed. The process should be streamlined and made more cost-effective for manufacturers, as the cost of getting products listed is a significant barrier for many.

What are your views on our assessment of issues with the way SAP currently recognises new technologies (currently the “Appendix Q process”)? Please provide your reasoning and any supporting evidence.

We agree with the issues identified around the Appendix Q process. In general, the process is too costly and time-consuming which can act as a barrier for new innovative products being recognised via SAP. The HEM must make it easier for innovative new products to become recognised.

What are your views on the principles for how the Home Energy Model will recognise new technologies once it is in use? Please provide your reasoning and any supporting evidence.

We support the principles set out in the consultation for the how the HEM will recognise new technologies. However, more detail is needed on how the process will work in practice. The reformed Appendix Q process should focus on reducing the cost burden and length of time that it takes for innovative technologies to gain recognition, as this can prove a significant barrier to new innovations entering the market and becoming commercially viable. Ultimately, the HEM needs to enable innovation rather than hinder it.

The opportunity for continuous evaluation should enable regular “live” updates to the HEM which may make it easier and quicker for new, innovative technologies that come onto the market to be recognised by the HEM. Greater integration with other innovation routes such as ECO4 is welcome to avoid the need for companies to duplicate unnecessarily a process which can be costly and time-consuming. More detail is required on how this integration will work in practice.

The ability of innovative technologies to become recognised within SAP also depends on the underlying measurement standard. If the underlying standard is not broad enough to cover innovative technologies, then it is difficult for them to be introduced.

What are your suggestions for other wrappers that could be developed for the Home Energy Model in future? Please provide your reasoning and any supporting evidence.

The proposals identify the main wrappers that should be included within the HEM, excluding the very important EPC wrapper which will be consulted on later this year. In general, we welcome the use of wrappers, as they should improve on the SAP process, however, the HEM’s modelling will only be as accurate as the data inputted into it, therefore it is important to choose the most suitable wrappers to achieve more accurate and reliable outputs.

The effectiveness of wrappers depends on how straightforward it is to interact with the core engine and what controls will be on it. At the moment, it is unclear how open the interface will be and how easy it will be to implement new wrappers. If it Is easy to add new wrappers and build software interfaces, then the wrapper system has the potential to be a lot more efficient than the current system, which can make producing an EPC quite a time-consuming and laborious process. If the wrapper process is efficient and accessible, it should be possible to quickly produce an output wrapper, whereas in SAP it can take hours to manually write up a report.

What are your views on the increased time resolution offered by the Home Energy Model? Please provide your reasoning and any supporting evidence.

The NIA welcomes the increased time resolution offered by the HEM. This will increase the accuracy of the HEM compared to SAP and bring a range of other benefits including:

• More accurate modelling of heat pump performance and importantly the interaction with other building elements within the whole building system.
• Better alignment of the HEM with improvements in real-time monitoring and evaluation of building performance. Enabling these improvements to be reflected within the model will enhance its accuracy and help to close the performance gap.
• More recognition of the benefits of smart technologies and the importance of energy flexibility.

Despite the clear benefits of increasing the time resolution, we are concerned by the longer runtime of the HEM which has been identified as an issue by the Government. Industry urgently needs more detail and clarity on exactly how long the expected runtime of the HEM will be. It is very important that the HEM still has a reasonable runtime that does not make the model impractical to run. For instance, a runtime of 5 minutes, although not ideal, would most likely still be workable for industry. By contrast, a runtime of 15 minutes or more would represent a substantial challenge for SAP users and would significantly reduce the effectiveness of the HEM in practice.

What are your views on the choice of BS EN ISO 52016-1:2017 (in its half-hourly
form) as the basis for the Home Energy Model? Please provide your reasoning and any supporting evidence.

The move to BS EN ISO 52016-1:2017 which is a recognised industry standard seems reasonable. There are clear benefits associated with moving to a standard that supports the HEM’s half-hourly simulation.

What are your views on the ability of the Home Energy Model to model energy flexibility and smart technologies? Please provide your reasoning and any supporting evidence.

The half-hourly time resolutions of the HEM gives it the potential to model energy flexibility much more accurately than SAP.

The usefulness of the HEM for modelling energy flexibility depends on the range of applications it is used for. The existing SAP methodology focuses on the building as an asset and ignores the occupants and their energy consumption habits in favour of standardised assumptions. The HEM’s potential for modelling energy flexibility is unlikely to be relevant when assessing a building’s compliance with building regulations for example, as this is solely based on the building’s performance as an asset. Energy flexibility is dependent on energy suppliers and occupants which is largely out of the control of developers and retrofit contractors.

It is clearly useful to have a model that can take into account energy flexibility and the use of smart technologies, particularly as these start to become more commonplace in homes. It is important to have a model that is responsive to changing patterns of energy consumption and the increased energy flexibility that smart technologies can bring for residents. However more detail is required from government on how it intends to use the HEM’s potential capabilities around energy flexibility and smart technologies. For instance, this could be used to model custom energy demand.

What are your views on the methodological approach for calculating space heating and cooling demand? Please provide your reasoning and any supporting evidence.

We support the methodological approach for calculating space heating and cooling demand. The new approach, as well as the use of more detailed inputs, will model the space heating demand of buildings more accurately than SAP. It is possible that it will lead to a higher space heating demand calculation than SAP, which will incentivise greater reductions in energy demand through increased fabric efficiency.

What are your views on the methodological approach for calculating fabric heat loss? Please provide your reasoning and any supporting evidence.

We agree with this approach.

What are your views on the methodological approach for calculating thermal bridges? Please provide your reasoning and any supporting evidence.

We agree with this approach.

What are your comments on the methodological approach for calculating infiltration and/or controlled ventilation? Please provide your reasoning and any supporting evidence.

We agree with the methodological approach for calculating infiltration. This should increase accuracy because it takes into account more factors and uses wind speeds updated on an hourly basis, making it much more receptive to changes in weather conditions. The omission of other contributing factors such as wind direction and “stack effect” from the HEM are unlikely to have a significant effect on the accuracy of the modelling. However, we would support their future inclusion, along with any other updates which increase the granularity and accuracy of the modelling. We also support replacing the fixed minimum dwelling ventilation rate with a wrapper input value as this will make the modelling more dwelling-specific.

What are your views on the methodological approach for calculating thermal mass? Please provide your reasoning and any supporting evidence.

We welcome the approach to include the entire building envelope within thermal mass calculations. This should produce a more accurate calculation than SAP 10.2 which only takes part of the construction envelope into account. Including warm up and cool down rates will also increase accuracy compared to the current approach based on a one-off, instantaneous value which doesn’t reflect how buildings warm up and cool down in practice.

While we support the desire to be as accurate and dwelling-specific as possible, we do not agree with the proposal to include the thermal mass of furniture in thermal mass calculations. Many properties, especially in the non-domestic sector, are unfurnished. It is not clear how the current approach would account for unfurnished properties. Furthermore, it doesn’t make sense for furniture to be taken into account when determining a building’s SAP rating or compliance with building regulations. This is often out of the control of developers and may depend on the personal choices of residents. We do not think that the negligible increase in accuracy that including furniture in thermal mass calculations will bring outweighs the issues that this approach may create.

What are your views on the methodological approach for calculating solar gains and solar absorption? Please provide your reasoning and any supporting evidence.

We support the approach for calculating solar gains and solar absorption, as it should provide more accurate results than the current version of SAP.

What are your views on the methodological approach for calculating heat losses from Domestic Hot Water pipework? Please provide your reasoning and any supporting evidence.

We are pleased to see that the model will take into account pipework, rather than using a standardised assumption. This will improve the accuracy of the model, as factors such as insulation levels can have a significant impact on heat losses from pipework.

However, the methodology does not seem to take into account the location of the pipework which could influence the calculation. It is important to distinguish between sections of pipework that are in the thermal envelope and those that are outside of it (in the roofwork, for instance) because heat loss from pipework in the thermal envelope could contribute to space heating, thereby skewing calculations.

What are your views on the methodological approach for calculating heat losses from hot water cylinders? Please provide your reasoning and any supporting evidence.

We agree with this approach.

What are your views on future features development for the Home Energy Model? Please make suggestions, explaining your reasoning.

We welcome the Government’s commitment to develop future features in the open. Given that there are key elements of the model which are yet to be finalised and may require further development, it is important that industry is properly consulted throughout its ongoing development, so that businesses can give their views and inform the development of aspects like future features.

The freedom to interact with the open-source code without too many restrictions will be important for software designers. This will allow them to build user interfaces and develop different end uses for the model without a prohibitive cost of entry.

What are your views on the inter-model validation work that has been carried out (i.e. comparison against SAP 10.2 and validation against PHPP and ESP-r)? Please provide your reasoning and any supporting evidence.

We agree with work carried out to benchmark against other models. This approach is sensible and takes account of the most relevant models. It is likely that the introduction of the HEM will shift the goalposts compared to SAP, most likely resulting in lower SAP scores and requiring higher standards of energy efficiency for compliance with building regulations. This is generally positive as it supports the transition towards more energy efficient, ‘Net Zero Carbon ready’ buildings. However, it is important that this aspect of the HEM’s implementation is carefully managed in a way that does not have a detrimental effect on residents, retrofit businesses, and others in the sector.

The findings of the inter-model validation seem to be generally positive. It is critical that these learnings, particularly the areas for improvement identified, are fully addressed in the next stage of the HEM’s development.

What are your views on the validation work that has been carried out against real-world case studies (i.e. IEA Annex 58, Camden Passivhaus, and Marmalade Lane)? Please provide your reasoning and any supporting evidence.

The validation work against real-world case studies is encouraging. It suggests a fairly high level of accuracy within the HEM when compared to real-world performance data. The Marmalade Lane case study findings show that the HEM was consistently more closely aligned with measured data than SAP 10.2, which is positive. This shows that the HEM is significantly more accurate than SAP in practice, and its introduction should help to close the performance gap between predicted and monitored energy use, which is one of the model’s primary aims.

What examples of real-world case studies, or other data, do you suggest be used to further validate the Home Energy Model? Please provide further information.

Contractors and software developers will run their own modelling using the open-source code. It is important that government carefully considers any feedback or issues that arise from independent modelling conducted by industry. It will also be important to gather more data on how residents’ behaviour affects the HEM’s modelling, as this is not explored in detail by the real-world case studies.

Click here to view the full document. 

Call for Evidence: Decarbonising home heating – National Insulation Association response

Decarbonising home heating – Committees – UK Parliament

Closing Date: 10 April 2024
Response submitted by: National Insulation Association
For more information, please contact: info@nia-uk.org
About the National Insulation Association The National Insulation Association (NIA) represents the insulation industry in the UK with a member base comprised of installers, system certificate holders, and manufacturers who provide a wide range of insulation solutions for homes and buildings. The NIA and its members are fully committed to maintaining and raising standards within the insulation industry.

Our response to the Call for Evidence

The NIA believe that a fabric first approach to home decarbonisation will provide the best outcomes for residents and best long-term value for money for government. A fabric first approach is the only way to ensure a just transition to net zero homes which does not result in higher energy bills for residents.

Heat pumps are expected to be the main low carbon heating technology for households going forward. In practice, the efficiency of heat pumps is receptive to the fabric efficiency of the home. A fabric first approach which ensures that the home is well-insulated prior to the installation of a heat pump will increase the system’s efficiency and reduce its running costs. Higher levels of insulation should also allow a smaller, cheaper heat pump to be installed that will have lower operating costs. Hence, a fabric first approach to decarbonisation is crucial to protect residents from overly high running costs and ensure that the switch to heat pumps is as affordable as possible for residents.

Since electricity is currently four times more expensive than gas per kWh1, there is a significant risk that, without energy demand reduction measures like insulation, households will be subject to higher energy bills when moving from a gas boiler to an electrified low carbon heating system. With an estimated 6 million households in fuel poverty, according to National Energy Action2, and 41% of all energy bill payers struggling to afford payments3, it is absolutely critical that the transition to decarbonised home heating does not result in higher energy prices for residents. Electricity prices are expected to remain well above pre-crisis levels for the rest of the decade4, therefore a sustainable long-term solution which reduces energy demand is needed in order to make the switch to electrified heating affordable for residents.

In the context of the ongoing energy crisis, the primary concern of the Government must be to make sure that residents are protected from higher energy prices. A fabric first approach to home decarbonisation is the best way to guarantee this in the long-term, as insulation measures reduce energy demand and bills for residents. This approach led to 145,000 households being lifted out of fuel poverty by energy efficiency measures between 2021 and 20225. Increased investment in energy efficiency measures will lift even more households out of fuel poverty in future and ensure that the transition to net zero homes is as affordable as possible for residents. This will make sure that the most vulnerable residents are protected throughout the transition to net zero. As the National Audit Office report points out, the Government has a legal commitment to both reduce emissions and meet its statutory fuel poverty targets6. By taking a fabric first approach to home decarbonisation, the Government can meet both of these legal obligations.

Short term investment in insulation measures not only delivers much-needed financial benefits to residents, it can also save the Government money in the long-term. It is expected that the decarbonisation of homes will be dominated by electrified low carbon technologies, meaning a vast expansion of the electricity network will be required to facilitate the roll out of electrified heating to the majority of homes. There is an enormous capital cost associated with developing more renewable generation capacity and expanding the electricity network to meet this increased demand. According to Ofgem and the Government, £170 billion – £210 billion will need to be invested in the grid by 2050 to achieve our net zero targets7. Therefore, demand reduction measures like insulation are vitally important to ensure that our homes use as little energy as possible to run. Investment in insulation in the short term could save the Government and taxpayers billions in the long run by reducing the extent to which we will need to expand the electricity network and build additional renewable energy capacity.

Insulation upgrades in the short term will also future-proof government and households against future energy crises. With a properly insulated housing stock, the Government will not need to spend billions on subsidising household energy bills in the event of future energy price shocks. For instance, in 2013, the Government decided to cut support for home insulation, which saw installation rates fall by around 90%8. Had the Government maintained 2013 levels of support for home insulation, this could have saved taxpayers £18 billion over the course of the Energy Price Guarantee, according to analysis conducted by the Energy & Climate Intelligence Unit9. Energy prices are set to remain high for the foreseeable future10, therefore, without increased investment in insulation, it is possible that the government may have to step in again with a very expensive support package should prices rise to unaffordable levels again. A fabric first approach to home decarbonisation would avoid this costly outcome and deliver value for money for government in the long term. Insulation measures offer a more cost-effective and permanent solution to high energy bills than nationwide energy bill support schemes. In this way, increased support for insulation now has the potential to save government and residents a significant amount of money in the future.

In addition to the significant financial savings it provides, insulation also has substantial health benefits for residents and wider society. Living in cold, damp homes can increase the risk of a number of illnesses, such as strokes, heart attacks, and respiratory diseases11. For instance, poorly insulated and ventilated homes can double the risk of children developing asthma12. Unfortunately, many homes are in this poor state, with 1 in 5 children in the UK currently exposed to damp and mould at home13. This highlights the urgent need to improve insulation and ventilation across our housing stock, thus helping to eliminate the scourge of damp and mould from homes along with the associated health issues they bring for residents which, as we have seen with the tragic case of Awaab Ishak, can be fatal(14)

The direct personal health benefits delivered by a fabric first approach to decarbonisation are also translated into wider public health and economic benefits to society. According to the Local Government Association, the NHS spends an estimated £2.5 billion per year on treating illnesses linked to cold, damp and unsafe homes15. This represents a significant burden on a health service which is already under significant funding pressures. A fabric first approach to home decarbonisation will create warmer, healthier homes and alleviate pressure on the NHS. Findings from the Energy Systems Catapult’s Warm Homes Prescription project found that enabling residents to live in warm, well-insulated homes reduced pressure on NHS services, with fewer hospital and GP appointments booked by those who had taken part in the trial16. The preventive health benefits it delivers makes insulation an excellent value for money investment for Government and taxpayers – investing £1 in retrofit is estimated to save £0.42 in direct health costs(17). Most importantly, a fabric first approach to decarbonisation will improve the personal health and wellbeing of residents, and enable people up and down the country to live in warmer, healthier and decarbonised homes.

Robust quality assurance is also crucial to ensure to ensure that public money is spent on high-quality installs which deliver the financial and health benefits outlined earlier without any unintended consequences. The Government must continue to ensure that public money is only spent on home decarbonisation projects that are delivered in accordance with the thorough quality assurance frameworks set out in PAS2030/35 and MCS. This is vital to protect consumers from harm. Without stringent quality assurance and consumer protections in place, there is a risk that the Government will open itself up to an increased number of legal complaints and compensation claims regarding sub-standard installs and property damage. As we rapidly increase the quantity of retrofit measures delivered over the coming years, it is imperative that we do not lose sight of the importance of quality. The race to net zero cannot become a race to the bottom in terms of quality standards. Any dilution in quality standards risks fatally undermining the net zero transition and irrevocably damaging consumer confidence in the home decarbonisation industry. Effective quality assurance is important to ensure that home decarbonisation measures deliver quality and value for money for government and residents.

Delivering home decarbonisation at scale without compromising on quality will require a significant increase in the size and skill level of the retrofit workforce. This represents a significant challenge, but also a huge opportunity. With sufficient targeted investment in retrofit skills and training, the Government has the opportunity to create thousands of high-quality, sustainable jobs in local communities across the UK. Based on the Climate Change Committee’s (CCC) projections, 120,000 to 230,000 jobs could be created across the UK construction sector in order to retrofit and insulate the UK housing stock – an 11% increase relative to the current size of the sector18. Importantly, these are also high-quality, skilled trades that pay well. According to Indeed, the average salary for an insulation worker in the UK is £37,17819 – above the national average. Most jobs in the insulation sector do not require a Level 6 qualification (undergraduate degree or equivalent), so employment in this sector will help to level up communities by providing high-skilled and well-paid technical employment for school leavers without a degree.

In addition, most energy efficiency work tends to be localised; therefore, installations will likely be carried out by local installers and businesses, thus ensuring that employment and growth opportunities remain within the local area where they are needed. Which’s recent Priority Places for Insulation Index report shows that many of the places most in need of future insulation upgrades are in deprived areas, for example former coalfields or coastal communities in the north of England20. As such, investment in insulation has the potential to support the Government’s levelling up mission by directing investment and jobs to areas that need it most. In this way, spending on insulation and wider retrofit skills represents a cost-effective investment for government because it creates well-paid, high-quality and sustainable jobs in local areas.

Despite the clear long-term benefits of insulation measures, we recognise that the upfront investment required can be costly for government. To mitigate this, we would like to see the Government provide more support for the development of innovative green finance mechanisms, which will make sure that home decarbonisation policies are cost-effective for government and taxpayers. The CCC estimates that retrofitting all of the UK’s housing stock will cost £250 billion by 205021. It is not reasonable or realistic to expect that government will provide fully funded grants to cover this cost. Neither can most households, many of whom have very limited savings22, be expected to fund the full upfront cost of retrofit without some form of support. Therefore, innovative green financing solutions which effectively mobilise private investment into the retrofit market and spread out the upfront cost of retrofit will be needed to ensure a net zero transition that is cost-effective for government. The Green Home Finance Accelerator represents a welcome start in this area, but the Government urgently needs to work with financial institutions and private investors to develop a range of effective green finance solutions that can be rolled out across the country. This is critical to create long-term, organic consumer demand for decarbonisation measures which is not reliant on expensive government subsidies.

In conclusion, a fabric first approach to decarbonising our homes represents the most effective way to fairly distribute the costs of the net zero transition. Short term investment in insulation will provide a number of longer term savings: reducing the cost of expanding the electricity network, avoiding the need for expensive energy bill support packages during future energy crises and providing significant public health savings, thereby reducing pressure on the NHS. Most importantly, a fabric first approach will enable residents to benefit from clean and affordable heating, along with improved health and comfort. Insulation is vital to ensure a just transition to net zero homes which protects the most vulnerable households in society.

1 Ofgem (2024). Energy price cap. Available here.
2 National Energy Action (2024). What is fuel poverty? Available here.
3 Office for National Statistics (2024). Cost of living insights: Energy. Available here.
4 Jillian Ambrose (2023). ‘Higher energy bills forecast for UK households next year’, The Guardian. Available here.
5 Department for Energy Security and Net Zero (2022). Fuel poverty factsheet: England, 2022. Available here.
6 National Audit Office (2024). Decarbonising home heating. Available here.
7 Regen (2023). Building a GB electricity network for net zero. Available here.
8 Rt Hon Chris Skidmore MP (2022). Mission Zero: Independent Review of Net Zero. Available here.
9 Energy & Climate Intelligence Unit (2022). Taxpayers facing £18 billion bill for failure to insulate UK homes. Available here.
10 Jillian Ambrose (2023). ‘Higher energy bills forecast for UK households next year’, The Guardian. Available here.

Click here to view the full document. 

The Home Energy Model: Making the Standard Assessment Procedure fit for a net zero future

The Home Energy Model (publishing.service.gov.uk)

Closing Date: 27 March 2024
Response submitted by: National Insulation Association
For more information, please contact: info@nia-uk.org

About the National Insulation Association
The National Insulation Association (NIA) represents the insulation industry in the UK with a member base comprised of installers, system certificate holders, and manufacturers who provide a wide range of insulation solutions for homes and buildings. The NIA and its members are fully committed to maintaining and raising standards within the insulation industry.

What are your views on the choice of name for the new model? Please provide your reasoning and any supporting evidence.

We are satisfied with the choice of name.

What are your views on the choice of name for the version of the model which is to be used to demonstrate compliance with the Future Homes Standard? Please provide your reasoning and any supporting evidence.

We are satisfied with the choice of name for the FHS assessment version of the HEM. It makes sense to include specific reference to the FHS, as this makes it clear what the model’s application will be and distinguishes it from the underlying model.

What are your views on using the open-source code as the approved methodology for regulatory uses of the Home Energy Model? Please provide your reasoning and any supporting evidence.

The NIA welcomes the move to publish the open-source code, as this will aid transparency and promote greater understanding of the methodology among relevant stakeholders. It will also give industry experts the chance to scrutinise the code and suggest improvements or raise any potential concerns. This should improve the overall effectiveness of the model.

If the open-source code is used as the approved methodology for regulatory uses of the HEM, we would like to see more clarity and guidance on what the process will be for dealing with errors in the code, in particular around liability and the transfer of risk. If there are errors with the centralised code, it is important that risk and liability is not transferred onto individual software providers who use the code as a basis for producing EPCs and determining compliance with building regulations. It is also important to avoid a situation whereby errors in the code become embedded into law.

It is important that making the open-source code the legal basis for the methodology does not act as a barrier to making necessary changes to the model in a swift manner. It must be possible for the HEM to be constantly improved and refined to improve its effectiveness. There is the potential that a codebase underpinned by regulation will be very slow to change. It is important that this does not act as a barrier to regular updates and improvements to the model. As mentioned earlier, if there are errors in the code, it is vital that these are rectified as soon as possible, without the need for a long, drawn-out regulatory process.

Whilst we agree with publishing the open-source code, it is important that other documents are published alongside it so that people not familiar with Python are still able to understand the methodology behind the model. It is encouraging to see that the Government will be publishing accompanying technical documents to provide further explanation about the model. This will ensure that the methodology is accessible to a wider range of people, thus aligning with the Government’s objective to make the HEM more transparent.

What forms of collaboration would you be interested in for future development of the Home Energy Model codebase? Please provide further details.

There must be a clear process for managing, evaluating and updating the codebase. It is important that industry is involved in this process so that they can shape the future development of the codebase.

What are your views on our assessment of issues with the current SAP delivery model? Please provide your reasoning and any supporting evidence.

We agree with the issues outlined with the current delivery model, however it is unclear how the HEM will resolve all of these, in particular the inertia of the SAP methodology. If the codebase is embedded in regulation, this could complicate and slow down the process of making changes to the methodology. Introducing a centralised, cloud-based version of the code has the potential to enable quicker updates to the methodology. However, it is not entirely clear how this would operate in practice and what the relationship would be with accompanying regulations.

Lack of accountability is a key issue, however it is still unclear from the consultation proposals where the balance of accountability will lie with the HEM. We would welcome clarity on who will be accountable, whether this be the Government, BRE, or independent software providers. If the Government proceeds with a centralised, cloud-based version of the HEM, this could simplify the issue of accountability.

At the moment, different software providers all have differing versions of SAP which can cause inconsistencies in results, although these tend to be small. Having a centralised, standardised code should help to minimise these inconsistencies in results. It should also help to clarify the accountability of different parties by providing one consistent version of the ‘truth’.

What are your views on the concept of a centralised, cloud-based version of the Home Energy Model, to be used for regulatory purposes? Please provide your reasoning and any supporting evidence.

We agree with the concept of a centralised, cloud-based version of the HEM. Currently, different software providers have differing versions of SAP which can lead to inconsistencies in results.

Centralising and standardising the model will help to increase accuracy and minimise these inconsistencies. The ability to make quick updates to the central platform is key.

It can be unclear where the balance of accountability lies with the current version of SAP, whereby different software providers implement differing versions of the methodology independently. Having a centralised, standardised model will help to clarify where accountability lies and transfer risk away from software providers. It is important that it is clear which body is ultimately responsible for the HEM (whether this be BRE or the Government).

The provider of the centralised model (BRE for example) will need to understand and put in place appropriate support arrangements to allow independent software providers to easily build user interfaces around the central platform.

What are your views on revising the database of product characteristics (currently the “PCDB”) for the Home Energy Model? Please provide your reasoning and any supporting evidence.

We agree with the intention to revise the database of product characteristics for the Home Energy Model. It is important that the PCDB is based on accurate and up-to-date data, and includes the most effective technologies currently on the market.

What changes would you recommend to the PCDB data collection procedures? Please provide your reasoning and any supporting evidence.

It is costly for manufacturers to get their products listed in the PCDB. This prohibitive cost means that many products are not listed on the database because it isn’t worth the effort and cost for manufacturers to apply for their products to be listed. The process should be streamlined and made more cost-effective for manufacturers, as the cost of getting products listed is a significant barrier for many.

What are your views on our assessment of issues with the way SAP currently recognises new technologies (currently the “Appendix Q process”)? Please provide your reasoning and any supporting evidence.

We agree with the issues identified around the Appendix Q process. In general, the process is too costly and time-consuming which can act as a barrier for new innovative products being recognised via SAP. The HEM must make it easier for innovative new products to become recognised.

What are your views on the principles for how the Home Energy Model will recognise new technologies once it is in use? Please provide your reasoning and any supporting evidence.

We support the principles set out in the consultation for the how the HEM will recognise new technologies. However, more detail is needed on how the process will work in practice. The reformed Appendix Q process should focus on reducing the cost burden and length of time that it takes for innovative technologies to gain recognition, as this can prove a significant barrier to new innovations entering the market and becoming commercially viable. Ultimately, the HEM needs to enable innovation rather than hinder it.

The opportunity for continuous evaluation should enable regular “live” updates to the HEM which may make it easier and quicker for new, innovative technologies that come onto the market to be recognised by the HEM. Greater integration with other innovation routes such as ECO4 is welcome to avoid the need for companies to duplicate unnecessarily a process which can be costly and time-consuming. More detail is required on how this integration will work in practice.

The ability of innovative technologies to become recognised within SAP also depends on the underlying measurement standard. If the underlying standard is not broad enough to cover innovative technologies, then it is difficult for them to be introduced.

What are your suggestions for other wrappers that could be developed for the Home Energy Model in future? Please provide your reasoning and any supporting evidence.

The proposals identify the main wrappers that should be included within the HEM, excluding the very important EPC wrapper which will be consulted on later this year. In general, we welcome the use of wrappers, as they should improve on the SAP process, however, the HEM’s modelling will only be as accurate as the data inputted into it, therefore it is important to choose the most suitable wrappers to achieve more accurate and reliable outputs.

The effectiveness of wrappers depends on how straightforward it is to interact with the core engine and what controls will be on it. At the moment, it is unclear how open the interface will be and how easy it will be to implement new wrappers. If it Is easy to add new wrappers and build software interfaces, then the wrapper system has the potential to be a lot more efficient than the current system, which can make producing an EPC quite a time-consuming and laborious process. If the wrapper process is efficient and accessible, it should be possible to quickly produce an output wrapper, whereas in SAP it can take hours to manually write up a report.

What are your views on the increased time resolution offered by the Home Energy Model? Please provide your reasoning and any supporting evidence.

The NIA welcomes the increased time resolution offered by the HEM. This will increase the accuracy of the HEM compared to SAP and bring a range of other benefits including:

• More accurate modelling of heat pump performance and importantly the interaction with other building elements within the whole building system.
• Better alignment of the HEM with improvements in real-time monitoring and evaluation of building Enabling these improvements to be reflected within the model will enhance its accuracy and help to close the performance gap.
• More recognition of the benefits of smart technologies and the importance of energy

Despite the clear benefits of increasing the time resolution, we are concerned by the longer runtime of the HEM which has been identified as an issue by the Government. Industry urgently needs more detail and clarity on exactly how long the expected runtime of the HEM will be. It is very important that the HEM still has a reasonable runtime that does not make the model impractical to run. For instance, a runtime of 5 minutes, although not ideal, would most likely still be workable for industry. By contrast, a runtime of 15 minutes or more would represent a substantial challenge for SAP users and would significantly reduce the effectiveness of the HEM in practice.

What are your views on the choice of BS EN ISO 52016-1:2017 (in its half-hourly form) as the basis for the Home Energy Model? Please provide your reasoning and any supporting evidence.

The move to BS EN ISO 52016-1:2017 which is a recognised industry standard seems reasonable. There are clear benefits associated with moving to a standard that supports the HEM’s half- hourly simulation.

What are your views on the ability of the Home Energy Model to model energy flexibility and smart technologies? Please provide your reasoning and any supporting evidence.

The half-hourly time resolutions of the HEM gives it the potential to model energy flexibility much more accurately than SAP.

The usefulness of the HEM for modelling energy flexibility depends on the range of applications it is used for. The existing SAP methodology focuses on the building as an asset and ignores the occupants and their energy consumption habits in favour of standardised assumptions. The HEM’s potential for modelling energy flexibility is unlikely to be relevant when assessing a building’s compliance with building regulations for example, as this is solely based on the building’s performance as an asset. Energy flexibility is dependent on energy suppliers and occupants which is largely out of the control of developers and retrofit contractors.

It is clearly useful to have a model that can take into account energy flexibility and the use of smart technologies, particularly as these start to become more commonplace in homes. It is important to have a model that is responsive to changing patterns of energy consumption and the increased energy flexibility that smart technologies can bring for residents. However more detail is required from government on how it intends to use the HEM’s potential capabilities around energy flexibility and smart technologies. For instance, this could be used to model custom energy demand.

What are your views on the methodological approach for calculating space heating and cooling demand? Please provide your reasoning and any supporting evidence.

We support the methodological approach for calculating space heating and cooling demand. The new approach, as well as the use of more detailed inputs, will model the space heating demand of buildings more accurately than SAP. It is possible that it will lead to a higher space heating demand calculation than SAP, which will incentivise greater reductions in energy demand through increased fabric efficiency.

What are your views on the methodological approach for calculating fabric heat loss? Please provide your reasoning and any supporting evidence.

We agree with this approach.

What are your views on the methodological approach for calculating thermal bridges? Please provide your reasoning and any supporting evidence.

We agree with this approach.

What are your comments on the methodological approach for calculating infiltration and/or controlled ventilation? Please provide your reasoning and any supporting evidence.

We agree with the methodological approach for calculating infiltration. This should increase accuracy because it takes into account more factors and uses wind speeds updated on an hourly basis, making it much more receptive to changes in weather conditions. The omission of other contributing factors such as wind direction and “stack effect” from the HEM are unlikely to have a significant effect on the accuracy of the modelling. However, we would support their future inclusion, along with any other updates which increase the granularity and accuracy of the modelling. We also support replacing the fixed minimum dwelling ventilation rate with a wrapper input value as this will make the modelling more dwelling-specific.

What are your views on the methodological approach for calculating thermal mass? Please provide your reasoning and any supporting evidence.

We welcome the approach to include the entire building envelope within thermal mass calculations. This should produce a more accurate calculation than SAP 10.2 which only takes part of the construction envelope into account. Including warm up and cool down rates will also increase accuracy compared to the current approach based on a one-off, instantaneous value which doesn’t reflect how buildings warm up and cool down in practice.

While we support the desire to be as accurate and dwelling-specific as possible, we do not agree with the proposal to include the thermal mass of furniture in thermal mass calculations. Many properties, especially in the non-domestic sector, are unfurnished. It is not clear how the current approach would account for unfurnished properties. Furthermore, it doesn’t make sense for furniture to be taken into account when determining a building’s SAP rating or compliance with building regulations. This is often out of the control of developers and may depend on the personal choices of residents. We do not think that the negligible increase in accuracy that including furniture in thermal mass calculations will bring outweighs the issues that this approach may create.

What are your views on the methodological approach for calculating solar gains and solar absorption? Please provide your reasoning and any supporting evidence.

We support the approach for calculating solar gains and solar absorption, as it should provide more accurate results than the current version of SAP.

What are your views on the methodological approach for calculating heat losses from Domestic Hot Water pipework? Please provide your reasoning and any supporting evidence.

We are pleased to see that the model will take into account pipework, rather than using a standardised assumption. This will improve the accuracy of the model, as factors such as insulation levels can have a significant impact on heat losses from pipework.

However, the methodology does not seem to take into account the location of the pipework which could influence the calculation. It is important to distinguish between sections of pipework that are in the thermal envelope and those that are outside of it (in the roofwork, for instance) because heat loss from pipework in the thermal envelope could contribute to space heating, thereby skewing calculations.

What are your views on the methodological approach for calculating heat losses from hot water cylinders? Please provide your reasoning and any supporting evidence.

We agree with this approach.

What are your views on future features development for the Home Energy Model? Please make suggestions, explaining your reasoning.

We welcome the Government’s commitment to develop future features in the open. Given that there are key elements of the model which are yet to be finalised and may require further development, it is important that industry is properly consulted throughout its ongoing development, so that businesses can give their views and inform the development of aspects like future features.

The freedom to interact with the open-source code without too many restrictions will be important for software designers. This will allow them to build user interfaces and develop different end uses for the model without a prohibitive cost of entry.

What are your views on the inter-model validation work that has been carried out (i.e. comparison against SAP 10.2 and validation against PHPP and ESP-r)? Please provide your reasoning and any supporting evidence.

We agree with work carried out to benchmark against other models. This approach is sensible and takes account of the most relevant models. It is likely that the introduction of the HEM will shift the goalposts compared to SAP, most likely resulting in lower SAP scores and requiring higher standards of energy efficiency for compliance with building regulations. This is generally positive as it supports the transition towards more energy efficient, ‘Net Zero Carbon ready’ buildings. However, it is important that this aspect of the HEM’s implementation is carefully managed in a way that does not have a detrimental effect on residents, retrofit businesses, and others in the sector.

The findings of the inter-model validation seem to be generally positive. It is critical that these learnings, particularly the areas for improvement identified, are fully addressed in the next stage of the HEM’s development.

What are your views on the validation work that has been carried out against real- world case studies (i.e. IEA Annex 58, Camden Passivhaus, and Marmalade Lane)? Please provide your reasoning and any supporting evidence.

The validation work against real-world case studies is encouraging. It suggests a fairly high level of accuracy within the HEM when compared to real-world performance data. The Marmalade Lane case study findings show that the HEM was consistently more closely aligned with measured data than SAP 10.2, which is positive. This shows that the HEM is significantly more accurate than SAP in practice, and its introduction should help to close the performance gap between predicted and monitored energy use, which is one of the model’s primary aims.

What examples of real-world case studies, or other data, do you suggest be used to further validate the Home Energy Model? Please provide further information.

Contractors and software developers will run their own modelling using the open-source code. It is important that government carefully considers any feedback or issues that arise from independent modelling conducted by industry. It will also be important to gather more data on how residents’ behaviour affects the HEM’s modelling, as this is not explored in detail by the real- world case studies.

Click here to view the full response. 

The Future Homes and Buildings Standards: 2023 consultation

The Future Homes and Buildings Standards: 2023 consultation – GOV.UK (www.gov.uk)

Closing Date: 6 March 2024
Response submitted by: National Insulation Association
For more information, please contact: info@nia-uk.org

About the National Insulation Association
The National Insulation Association (NIA) represents the insulation industry in the UK with a member base comprised of installers, system certificate holders, and manufacturers who provide a wide range of insulation solutions for homes and buildings. The NIA and its members are fully committed to maintaining and raising standards within the insulation industry.

Which option for the dwelling notional buildings (for dwellings not connected to heat networks) set out in The Future Homes Standard 2025: dwelling notional buildings for consultation do you prefer?

1. Option 1 (higher carbon and bill savings, higher capital cost)

Option 1 is our preferred option because Option 2, as the Government’s own modelling shows, would leave residents exposed to higher annual energy bills than the 2021 uplift to Part L. The FHS should not under any circumstances lead to higher energy bills for residents than existing new build standards. This would be a completely unacceptable outcome. Therefore, we do not consider Option 2 to be a viable option. Furthermore, as outlined by a cross-industry letter sent to the Secretary of State for Levelling Up, Housing and Communities, there is a risk that Option 2 would contravene the Government’s public sector equality duty by introducing a standard which ‘would unduly affect those on lower incomes’.1

While we support Option 1 over Option 2, it is worth noting that these are the two least ambitious options of the five considered by the Future Homes Hub in their ‘Ready for Net Zero’

Report.2 For instance, home heating demand in the Report’s Contender Specification 4 is just % of that in Option 1 of the FHS, meaning that the options under consideration in the FHS will incur significantly higher bills and carbon emissions. The NIA believe that the U-values outlined in the Option 1 specification need to be tightened further for a number of reasons.

• To protect residents from high energy Heating systems installed under the FHS are expected to be dominated by electrified options like heat pumps. The high electricity to gas price ratio (3.86 to 1 as of the January 2024 price cap level)3means that without significant energy demand reduction measures, residents with electrified heating will be exposed to high energy bills. As such, insulation measures which lower energy demand are especially important with electrified heating options. More ambitious insulation requirements will mean that households living in new builds with electric heating are protected from the risk of high energy bills. This is particularly important given the current cost-of-living and energy crises, with electricity prices expected to remain well above pre-crisis levels for the rest of the decade.4 Therefore, the NIA would like to see stricter U-values to protect vulnerable consumers from high electricity prices.
• To increase the efficiency and reduce the running costs of heat The efficiency of heat pumps is receptive to the fabric efficiency of the home. Introducing more ambitious U-values will increase the efficiency of heat pumps and reduce the cost they incur to run. Higher insulation standards should allow a smaller, cheaper heat pump to be installed that will have lower operating costs for residents. Real-world monitoring and testing is key to find out how the fabric works in practice, enabling more accurately sized heating systems to be installed. Correctly sized heat pumps will operate at a higher efficiency than incorrectly sized systems. Ambitious fabric standards bolstered by effective monitoring and testing will result in more efficient and cheaper-to-run heating systems.
• To reduce the cost of electricity network expansion. If the majority of new (and ultimately existing) homes are to replace gas with electric heating, a huge expansion of the electricity grid will be required. There is a huge capital cost associated with building more renewable generation capacity and expanding the electricity network. According to Ofgem and the Government, £170bn – £210bn will need to be invested in the grid by 2050 to achieve our net zero targets.5Therefore, it is imperative that we build homes which use as little electricity to run as possible because the cheapest energy is the energy we don’t use. High insulation standards which reduce the energy demand of new homes will reduce the scale by which the electricity network and additional renewable capacity will need to be expanded by, thus saving billions in capital costs for residents and government. It will also increase energy security by reducing our demand for energy imports from overseas.

¹ Good Homes Alliance (2024). Future Homes Standard Consultation Response. Available at: Future Home Standard response – Good Homes Alliance
² Future Homes Hub (2023). Ready for Zero: Evidence to inform the 2025 Future Homes Standard. Available at: Ready for Zero – Evidence to inform the 2025 Future Homes Standard -Task Group Report FINAL- 280223- MID RES.pdf (cdn-website.com)
³ Ofgem (2024). Energy price cap. Available at: Energy price cap | Ofgem
⁴ Jillian Ambrose (2023). ‘Higher energy bills forecast for UK households next year’, The Guardian. Available at: Higher energy bills forecast for UK households next year | Energy bills | The Guardian
⁵ Regen. Building a GB electricity network ready for net zero. Available at: Building a GB electricity network for net zero (regen.co.uk)

What are your priorities for the new specification? (select all that apply)

Our priorities for the new specification are:

• Lower energy Lower energy bills are a vital consideration, particularly in the context of the ongoing cost of living and energy crises. The FHS should make every effort to reduce energy bills for residents. For this reason, we support Option 1 which would result in significantly lower energy bills compared to current new build standards. However, as outlined in our response to Question 7, we believe that Option 1 should be more ambitious in terms of insulation. Setting higher insulation standards, in conjunction with the solar PV provisions in Option 1, would ensure that energy bills are as affordable as possible for residents.
• Carbon savings. Higher insulation standards would also have the added advantage of additional carbon savings. The generation emissions factor for grid electricity in the UK is still around 0.2 kg CO2e per kWh.⁶This means that every unit of electricity consumed carries with it associated CO2 Given that the Government does not expect the UK’s electricity grid to be fully decarbonised until 20357, it is imperative that new homes consume as little electricity as possible. The most effective way to do this is by setting higher minimum insulation standards within the FHS.
• Protecting residents’ health. Option 1 sets higher ventilation standards, which are important to prevent the risk of damp and mould, and the potential health issues associated with it. However, we think that Option 1 could also be more ambitious when it comes to ventilation. For instance, it could require mechanical ventilation with heat recovery (MVHR). This would improve air quality, and reduce the risk of condensation and mould, while also conserving heat Strict ventilation minimum requirements are important to go along with increased insulation and airtightness requirements. A combination of high insulation and ventilation standards are the best way to protect residents’ health.
• Reducing pressure on the electricity grid and the capital cost needed to upgrade it. As mentioned in Question 7, the electrification of heat will necessitate a huge expansion of the electricity grid, which comes with a large capital cost associated with building more renewable generation capacity and expanding the electricity network. Therefore, high standards around insulation and solar PV are important to reduce the electricity that new homes require from the grid. This will increase our energy security and save billions in capital costs for government and taxpayers.

⁶ ITPEnergised (2023). New UK grid emissions factors 2023. Available at: New UK Grid Emissions Factors 2023 – ITPEnergised
⁷ Carbon Brief (2023). CCC: Here’s how the UK can get reliable zero-carbon electricity by 2035. Available at: CCC: Here’s how the UK can get reliable zero-carbon electricity by 2035 – Carbon Brief

Which option for the dwelling notional buildings for dwellings connected to heat networks set out in The Future Homes Standard 2025: dwelling notional buildings for consultation do you prefer?

a. Option 1 (higher carbon and bill savings, higher capital cost)

Which option do you prefer for the proposed non-domestic notional buildings set out in the NCM modelling guide?

a. Option 1

What are your priorities for the new specification?

Our priorities for the new specification are:

• Lower energy bills. For commercial buildings, lower bills are important to enable businesses to reduce their overhead costs, which continue to be a significant burden for many during the energy crisis. A survey conducted by PwC in 2023 found that 77% of business respondents had to raise their prices over the past two years as a result of energy-related expenditures8, thus driving inflation across the economy. Moreover, reducing the percentage of their budget spent on overhead costs will enable businesses to invest more in productive activities, such as hiring and training staff and creating economic growth. For this reason, we support Option 1 which would result in significantly lower energy bills compared to current standards. However, we believe that Option 1 should be more ambitious in terms of insulation standards, as set out in our responses to Questions 7 and 8.
• Carbon savings. Our preferred choice is Option 1 as it would deliver higher carbon savings. However, we would like to see higher insulation standards, as mentioned in our responses to Questions 7 and 8.
• Reducing pressure on the electricity grid and the capital cost needed to upgrade As mentioned in Questions 7 and 8, high standards for insulation and solar PV are important to reduce the electricity that new buildings require from the grid. This will increase our energy security and save billions in capital costs for government and taxpayers.

⁸ Sidhi Mittal (2024). ‘British businesses struggling to find right solutions to cut energy costs, survey finds’, Edie. Available at: UK Businesses Grapple with Rising Energy Costs According to PwC Survey (edie.net)

Do you agree that the metrics suggested above (TER, TPER and FEE) be used to set performance requirements for the Future Homes and Buildings Standards?

a) Yes, and I want to provide views on the suitability of these metrics and/or their alternatives.

We agree with the three metrics suggested, however we would like to see an additional metric added to take into account the building’s real-world fabric performance. This additional metric would be based on the results of mandatory post occupancy testing, which we have outlined our support for in Question 40. This Actual/Real Fabric Energy Efficiency metric could be compared to the DFEE to test how the property’s real-world fabric performance compares to its target DFEE rate. Including this as an additional metric would help to close the performance gap between how homes are designed and built. This would give residents and government confidence that buildings are actually being constructed in practice to the standards stipulated by the FHS and Building Regulations.

Mandatory post-occupancy testing, backed up by a metric that measures real-world fabric performance, would reward good performance from housebuilders and retrofit businesses, and generally drive up quality standards across the housing sector.

Do you agree with the proposed changes to minimum building services efficiencies and controls set out in Section 6 of draft Approved Document L, Volume 1: Dwellings?

Yes.

Do you agree with the proposed changes to Section 4 of draft Approved Document L, Volume 1: Dwellings, designed to limit heat loss from low carbon heating systems?

Yes.

Do you agree with the proposed guidance on the insulation standard for building heat distribution systems in Approved Document L, Volume 2: Buildings other than dwellings?

Yes.

Do you agree that the current guidance for buildings with low energy demand which are not exempt from the Building Regulations, as described in Approved Document L, Volume 2: Buildings other than dwellings should be retained without amendment?

Yes.

Should we set whole-building standards for dwellings created through a material change of use?

Yes.

Should the proposed new MCU standard apply to the same types of conversion as are already listed in Approved Document L, Volume 1: Dwellings?

No, standards should also apply to non-dwelling accommodation e.g., student or patient accommodation, care homes, and hotels. In many of the buildings classified as non-dwelling accommodation, residents live there on a semi-permanent basis. We do not believe that buildings which are used as a main place of residence for a significant proportion of the year, such as care homes, patient accommodation, and student accommodation, should be subject to weaker energy efficiency requirements than residential conversions.

Care homes and patient accommodation are used to house some of the most vulnerable people in society, who may be more susceptible to living in cold, damp and inefficient homes. Thus, it is crucial that these types of non-dwelling accommodation are subject to high MCU energy efficiency requirements.

Should different categories of MCU buildings be subject to different requirements?

Yes.

Which factors should be taken into account when defining building categories? (check all those that apply)

The following factors should be taken into account when defining building categories:

• height of the building, e., low versus mid- to high-rise buildings
• floor area of the building
• whether the conversion is a part- or whole-building conversion

Do you agree with the illustrative energy efficiency requirements and proposed notional building specifications for MCU buildings?

Yes.

If you answered no to the previous question, please provide additional information to support your view. Select all that apply. The requirements are:

Not applicable.

Do you agree with using the metrics of primary energy rate, emission rate and fabric energy efficiency rate, if we move to whole dwelling standards for MCU buildings?

Yes, and I want to provide additional suggestions or information to support my view.

As outlined in our response to Question 12, we would also support the inclusion of a metric that measures real-world fabric performance.

Under what circumstances should building control bodies be allowed to relax an MCU standard?

Building control bodies should be allowed to relax an MCU standard under the following circumstances:

• The technical or practical feasibility of achieving the It is important that buildings subject to an MCU are upgraded to the highest possible standards of energy efficiency. However, in some cases, we accept that it may not be technically or practically feasible to reach the required standards, for example, if there is no space or access to install the required insulation.
• Consideration of historic and traditional dwellings. We also recognise that reaching the required MCU standard might not be possible or practical in some historic and traditional buildings, particularly where listed building or conservation status applies.

Do you have views on how we can ensure any relaxation is applied appropriately and consistently?

As set out in our response to Question 32, we recognise that there are certain circumstances where MCU standards may need to be relaxed for practical purposes. However, it is crucial that any exemptions to the standards are robustly policed and accompanied by clear guidance to make sure that developers are only granted exemptions when there is a genuine barrier preventing adherence to the standards. Wherever practically possible, developers must be required to meet high energy efficiency standards in order to ensure that the benefits of energy efficiency measures for the climate and building occupants are fully realised.

Therefore, the NIA believe that the following should be in place to ensure any relaxation is applied appropriately and consistently:

• Only formal relaxation or dispensation through the local authority should be
• There should be guidance on circumstances where relaxation of the notional standard may be appropriate so that it is clear and unambiguous for developers when they are and are not required to meet MCU standards.

Should a limiting standard be retained for MCU dwellings?

Yes.

Even in dwellings where it is not possible to achieve the MCU whole building standard, there should still be minimum limiting standards for fabric insulation. These minimum standards are important to safeguard occupants from high energy bills.

They are also critical to prevent building defects from occurring. If there are sub-standard levels of insulation and ventilation within MCU dwellings, there will be a significantly increased risk of damp and mould, which poses a serious threat to residents’ health.

If a limiting standard is retained, what should the limiting standard safeguard against?

Limiting standards should be retained and they should safeguard against:

• risk of moisture, damp and mould
• high energy demand and energy bills

Do you agree that a BREL report should be provided to building control bodies if we move to energy modelling to demonstrate compliance with MCU standards?

Yes, and photographic evidence is needed.

Do you agree that consumers buying homes created through a material change of use should be provided with a Home User Guide when they move in?

Yes, and I’d like to provide further information.

We agree that consumers buying MCU homes should be provided with a Home User Guide when they move in. Supporting information and advice is important to make sure consumers operate energy efficiency technologies in a way that maximises their efficiency and effectiveness. This is particularly important when it comes to operating low carbon and smart technologies that they may be unfamiliar with.

Do you agree that homes that have undergone an MCU should be airtightness tested?

Yes, and I’d like to provide further information.

Airtightness testing will help to enforce fabric requirements by ensuring that the building fabric performs in practice as modelled. We would support mandatory airtightness testing for all homes including those that have undergone an MCU. This should be accompanied by increased minimum ventilation standards as a higher level of airtightness without sufficient ventilation can increase the risk of condensation and mould.

Do you think that we should introduce voluntary post occupancy performance testing for new homes?

Yes, and I’d like to provide further information.

Introducing post occupancy performance testing will help to protect consumers from experiencing higher bills and lower comfort levels. It will also build consumer confidence in the benefits of energy efficiency measures and the quality of work being carried out by the industry. However, we would like to see post occupancy performance testing implemented as a mandatory requirement, rather than a voluntary measure. Historically, voluntary options have seen very low uptake, therefore implementing this as a voluntary measure will likely result in only a small uptake in occupancy testing, and create an unfair market.

In addition, this approach creates a risk for housebuilders, as those who engage with post occupancy testing could be penalised for reporting the post occupancy testing results – as without mandated testing, 100% compliance is assumed.

Post occupancy testing ensures that homeowners get maximum benefit and the lowest possible bills from purchasing a new home, by reassuring them that their home achieves the efficiency level promised in the design in practice. Post occupancy testing is also important to ensure that homes have correctly sized heating systems, particularly as incorrectly sized heat pumps will

operate at a lower efficiency than correctly sized ones. Real-world monitoring and testing is crucial to find out how the fabric works in practice. This measurement will enable more accurately sized heating systems to be installed and ensure the house operates as an efficient whole house system. It is crucial that the fabric meets its target design efficiency in practice under real-world occupancy.

Mandatory testing should instead be introduced through sampling a percentage of homes to ensure compliance. For example, occupancy testing could be mandated for 10% of completions. Mandating post occupancy testing and making results publicly available will assist with improving quality and provide evidence for real-world efficiencies to monitor effectiveness and non- compliance with standards. This knowledge would help to improve the overall quality of the industry, alleviating the performance gap and raising consumer confidence. There is likely to be a significant performance gap without mandatory post occupancy testing.

Do you think that the government should introduce a government-endorsed Future Homes Standard brand? And do you agree permission to use a government-endorsed Future Homes Standard brand should only be granted if a developer’s homes perform well when performance tested? Please include any potential risks you foresee in your answer.

Yes, and I want to provide additional suggestions or information.

Implementing a government-endorsed Future Homes Standard brand is a positive way to incentivise housebuilders to engage with post occupancy testing to improve and maintain quality standards.

However, there must be a robust quality assurance process in place to ensure that the brand is credible and trustworthy, or risk damaging consumer confidence in the FHS. The brand should only be awarded to housebuilders that have consistently high-quality outputs, and not simply for those who measure performance. This aligns with leading a ‘race to the top’ on quality within the market. If there is not a robust process in place that only rewards consistently high-quality completions, the brand will not achieve the intended purpose and consumers will have difficulty differentiating between good quality and poor quality homes.

In addition, a Future Homes Standard brand is a good opportunity to introduce a public awareness campaign to improve consumer education about energy efficiency measures and standards. This could help with tackling the performance gap regarding the issue of user behaviour.

Do you agree with the proposed changes to Approved Document F, Volume 1: Dwellings to improve the installation and commissioning of ventilation systems in new and existing homes?

Yes, and I’d like to provide further information

We support the proposed changes, as more rigorous testing should lead to higher quality installations of ventilation systems and reduce the risk of condensation and mould resulting from sub-standard installs.

Nonetheless, we recognise that the increased cost of testing equipment, such as calibrated powered flow hoods, represents a barrier to compliance for some contractors. Therefore, we would urge the Government to provide support for contractors to purchase the necessary equipment. This will increase rates of compliance with the new ventilation rules and lead to higher quality across the insulation and ventilation sector.

Do you agree with the proposal to extend Regulation 42 to the installation of mechanical ventilation in existing homes as well as new homes?

We support increased testing of ventilation systems installed into existing homes. This will ensure that ventilation systems installed into residents’ homes are installed correctly and perform as intended. More extensive testing should reduce the incidence of poor quality installs, which can have damaging consequences for residents.

Do you agree with proposed changes to Approved Document L, Volume 1: Dwellings and Approved Document F, Volume 1: Dwellings to (a) clarify the options for certifying fixed building services installations and (b) set out available enforcement options where work does not meet the required standard?

Yes, and I’d like to provide further information.

We welcome further clarity on the options for certifying fixed building services. It is crucial that robust monitoring and enforcement mechanisms are in place to make sure that work is being carried out to the required standard. To this end, it is clear that building control bodies need more resources in order to properly enforce compliance with Building Regulations. For the Future Homes Standard to achieve its objectives, it is absolutely essential that it is backed up by effective enforcement mechanisms.

Do you have a view on how Home User Guides could be made more useful and accessible for homeowners and occupants, including on the merits of requiring developers to make guides available digitally? Please provide evidence where possible.

Yes, (please provide further details)

Developers should be required to make guides available digitally alongside paper copies. It is important that information is easily accessible for existing and also future residents. It can be very difficult for residents to find out property-specific information when they move into a new home, including details of any historic building works or retrofit works that have been carried out. Making Home User Guides digitally available and searchable via a centralised online database would make it much easier for residents to find out important information and help them to maintain their home more effectively. Many consumers may be unfamiliar with some of the technologies installed in new homes, so Home User Guides available digitally are vital to aid

their understanding of new technologies and how to operate them effectively.

Do you think that local authorities should be required to ensure that information required under Regulations 39, 40, 40A and 40B of the Building Regulations 2010 has been given to the homeowner before issuing a completion certificate?

Yes.

Do you agree that it should be possible for Regulation 26 (CO2 emission rates) to be relaxed or dispensed with if, following an application, the local authority or Building Safety Regulator concludes those standards are unreasonable in the circumstances?

Yes, but we believe that relaxation should only be allowed in exceptional circumstances, if for instance, the required energy efficiency measures cannot be installed safely. Use of this power must be policed and monitored very closely to ensure that it is not being used as a loophole to undercut energy efficiency standards without very good reason.

Do you think that local authorities should be required to submit the applications they receive, the decisions they make and their reasoning if requested?

Yes, and I’d like to provide further justification.

If Regulation 26 is subject to potential relaxation or dispensation, the relaxation process must be monitored very closely. Local authorities should be required to submit records of their decisions and the justifications for making them. This is essential to ensure that relaxation powers are not abused and do not become a convenient loophole by which developers can bypass the Future Homes and Buildings Standard.

Local Authorities’ use of these powers should be monitored closely and subject to enforcement action if necessary. For instance, if certain Local Authorities are found to be granting particularly high numbers of dispensations compared to others, an investigation may be required into whether they are abusing dispensation powers, accompanied by appropriate enforcement action if abuses are found to have been taking place.

Are there any additional safeguards you think should be put in place to ensure consistent and proportionate use of this power?

As noted in our response to Question 63, stringent monitoring and enforcement is critical to ensure consistent and proportionate use of this power.

Do you agree that Part L1 of Schedule 1 should be amended, as above, to require that reasonable provision be made for the conservation of energy and reducing carbon emissions?

Yes.

Do you agree that regulations 25A and 25B will be redundant following the introduction of the Future Homes and Buildings Standards and can be repealed?

Yes.

Do you agree that the Home Energy Model should be adopted as the approved calculation methodology to demonstrate compliance of new homes with the Future Homes Standard?

Yes, and I’d like to provide further information.

We agree with the use of the Home Energy Model (HEM) as the approved methodology to demonstrate compliance with the FHS. A replacement for SAP is long overdue and we welcome the increased accuracy that the HEM will bring.

However, given the tight timelines involved and the fact that the HEM is not yet finalised, there is a risk that it may not be ready for the introduction of the FHS. The Government’s consultation on the HEM makes it clear that the HEM is still undergoing development in multiple areas and lacks detail on certain aspects of the model’s design. The Government must work quickly to ensure that the HEM is fully finalised and any major issues with its design are resolved by the time the FHS is introduced. It is absolutely essential that the introduction of the FHS is not pushed back due to issues or delays with the HEM.

Do you agree with the revised guidance in The Future Homes Standard 2025: dwelling notional buildings for consultation no longer includes the average compliance approach for terraced houses?

Yes.

Do you agree with the proposed approach to determine U-values of windows and doors in new dwellings?

Yes.

Do you agree with the proposal to remove the default y-value for assessing thermal bridges in new dwellings?

Yes.

Which option describing transitional arrangements for the Future Homes and Buildings Standard do you prefer? Please use the space provided to provide further information and/or alternative arrangements.

Option 1

Option 1 provides an adequate transitionary period, whilst ensuring that we continue the momentum towards net zero targets. Furthermore, this option is followed by a separate 12-month transitional period anyway, which should minimise the impact on developers.

Do you agree that the 2010 and 2013 energy efficiency transitional arrangements should be closed down, meaning all new buildings that do not meet the requirements of the 2025 transitional arrangements would need to be built to the Future Homes and Buildings Standards?

Yes.

The NIA agree that the 2010 and 2013 energy efficiency transitional arrangements should be closed so that all new buildings are built to the Future Homes and Buildings Standards. Maintaining previous standards would be incompatible with reaching net zero targets and unfair for consumers who would be burdened with the costs of retrofitting a home built to old, outdated standards. This transition is fairest for the consumer, drives the construction industry to adopt more sustainable practices and aligns with net zero targets. To aid this transition, information, advice and guidance should be in place to support homeowners and housebuilders through the transition.

Click here to view the full response.

Consultation Response – Consultation on a new Social Housing Net Zero Standard in Scotland

Consultation on a new Social Housing Net Zero Standard in Scotland (www.gov.scot)

Closing Date: 8 March 2024
Response submitted by: National Insulation Association
For more information, please contact: info@nia-uk.org
About the National Insulation Association

The National Insulation Association (NIA) represents the insulation industry in Scotland and across the UK with a member base comprised of installers, system certificate holders, and manufacturers who provide a wide range of insulation solutions for homes and buildings. The NIA and its members are fully committed to maintaining and raising standards within the insulation industry.

Questionnaire

To what extent do you support the use of a fabric efficiency rating, based on heat demand, in the SHNZS?

Strongly support

The NIA supports the use of a fabric efficiency rating that goes beyond EPCs to focus solely on the building fabric and how well it retains heat and mitigates unwanted heat gains. A well-insulated and airtight building fabric is critical for maximising the efficiency of heating systems and minimising energy bills for residents. By prioritising fabric efficiency, the standard can better ensure that tenants benefit from clean heating systems, particularly for heat pump systems, which can perform exceptionally well in tightly sealed and well-insulated environments, further enhancing the efficiency and reducing the overall energy consumption of homes.

Of the options presented for the fabric efficiency rating, which one do you support for the new SHNZS?

Option 2
The NIA supports a fabric energy efficiency rating based on space heating demand only, to reduce external influences on the rating such as consumer behaviour. Meeting the fabric efficiency rating is essential to ensure social housing across Scotland is ready for the transition to clean heat. The NIA supports providing a target range to account for harder to treat property types. Option 2 mitigates the obvious issue of social housing providers aiming for the lower end of the range by providing an additional target to reach 71 kWh m2/year or better by 2040. That said, staggering this requirement by allowing a further 7 years to achieve the fabric efficiency rating will negatively impact tenants and cause further disruption, including some who may be living within vulnerable circumstances. The NIA advocates for meeting the higher end of the fabric efficiency rating and incentivising social housing providers to complete all works at once. This is the most effective way to retrofit homes both in terms of cost and quality, and minimises disruption to residents. We would support enforcing the higher end of the range by 2033, in properties where this is cost effective and feasible to do so. This approach reduces the risk that having a target range will disincentivising a best-practice, whole house approach to retrofit in easier to treat properties where this is feasible. Flexibility and/or additional time could be granted in harder to treat properties where meeting the higher end of the range is not cost effective or feasible with the requirement to reach 120kWh/m2/year as a minimum.

Are there additional options for the fabric efficiency rating that you think should be included? If yes, please describe these here.

The NIA advocates for meeting the higher end of the fabric efficiency rating and incentivising social housing providers to complete all works at once. This is the most effective way to retrofit homes both in terms of cost and quality, and minimises disruption to residents. We would support enforcing the higher end of the range by 2033, in properties where this is cost effective and feasible to do so. This approach reduces the risk that having a target range will disincentivising a best-practice, whole house approach to retrofit in easier to treat properties where this is feasible. Flexibility and/or additional time could be granted in harder to treat properties where meeting the higher end of the range is not cost effective or feasible with the requirement to reach 120kWh/m2/year as a minimum.

What, if any, are your views on how performance against the fabric efficiency rating should be measured?

The NIA advocates for a robust process to measure whether the fabric of homes actually meets its target design efficiency under real-world occupancy to protect residents and ensure that properties are ready for the transition to clean heat. Mandatory and accurate real-world performance monitoring (through sampling) is one way of reducing risk. Social housing providers could also make use of innovative technologies to measure performance which consider user behaviour and occupancy to determine actual energy performance. This will also incentivise high quality retrofit and ensure that residents reap the true benefits of retrofit measures in practice. Social housing providers should engage with tenants as early as possible during the retrofit process to effectively manage and implement this.

What are your views, if any, on the proposal for a minimum fabric efficiency standard?

The Scottish Government have recently consulted on EPC reform, therefore we expect the accuracy of EPCs will improve after the introduction of the new metrics that more accurately reflect the fabric efficiency of a home and support the transition to net zero. This will be further strengthened by the introduction of the Home Energy Model which will result in significantly more accurate and effective EPCs. EPCs take into account the individual property characteristics, whereas using a ‘one size fits all’ list that doesn’t consider property-specific characteristics creates a risk that the list of measures will become a ‘tick-box’ exercise that is irrelevant for certain property types.

It must be recognised and considered that properties have differing energy needs, and it is critical to ensure that residents have access to high quality, accessible advice to make sure that they can make informed choices about which measures are the most suitable for their property.

Should the Scottish Government proceed with a list of measures, we believe that solid wall insulation (IWI and EWI) should also be included on it. This is essential to make sure that solid wall homes are not left behind on the transition to net zero. For many solid wall properties, most or all of the measures on the proposed list will not be relevant, meaning that these homes will be subject to weaker energy efficiency standards. There is a risk that this will create a two-tiered society whereby those with solid walls will be subject to higher energy bills and colder homes than those without.

The proposed requirements reflect a commitment to providing warmer homes and lower bills for residents. However, they must also be accompanied by funding and support to enable social landlords to meet them. Therefore, the NIA recommends the implementation of additional support, resource and guidance to effectively deliver the proposed measures.

What, if any, are your views on whether homes should not be relet if they cannot meet a minimum fabric efficiency standard?

The proposal that social housing cannot be relet if the minimum standard is not met by 2028 does incentivise landlords to make the required changes, however the impact of this exacerbating housing shortages must be taken into account.

The proposed exemptions in Section 3.5 do mitigate this issue somewhat, however more could be done to ensure that a higher proportion of hard-to-treat properties receive much-needed energy efficiency measures. For example, rather than exempting properties in circumstances where social landlords share buildings with other tenures – if mixed tenure properties are unwilling or unable to contribute – funding streams, such as the Social Housing Net Zero Heat Fund, could include a percentage of funding allocated for ‘in-fill’ properties to mitigate this. This supports an area-based approach, allowing for economies of scale and addresses communities collectively.

What, if any, are your views on whether ventilation and monitoring strategies should be required where MVHR is not installed?

The NIA supports the proposition that landlords should be required to devise a ventilation and monitoring strategy to accompany energy efficiency interventions in cases where mechanical ventilation isn’t installed.

In particular, there should be a focus on monitoring to provide essential data to identify potential risks and ensure that air quality meets required standards under real-world occupancy – contributing to the well-being, comfort and health of tenants. Effective ventilation, backed up by stringent monitoring, will protect social housing tenants from health risks associated with damp and mould. The PAS 2035 process sets out clear ventilation requirements, hence it is vital that social housing retrofit is carried out by qualified installers subject to PAS standards. This is integral to an effective ventilation strategy.

Enforcing a mandatory ventilation and monitoring strategy would help to mitigate unintended consequences. There should be a clear process in place to ensure regulations are consistent and guidance and support should be put in place to assist landlords with implementing this.

To what extent do you support the need for landlords to have an element of discretion to ensure measures are cost effective and in the best interest of tenants?

Strongly support

The measures installed should always be in the best interest of tenants, and landlords should ensure that appropriate advice and guidance is provided to make sure that tenants are not in any way negatively impacted by measures, particularly financially. This includes considering disruption to tenants. Early and ongoing engagement throughout the retrofit process is crucial to achieve this.

A report issued by BEIS (now DESNZ) highlighted that tenant behaviour and lack of education and advice is a major barrier to social housing retrofit.1 Landlord discretion must be regulated and monitored to ensure the outcome is best for the tenants.

What, if any, are your views on whether targets should be varied by guidance from the Scottish Government in specific circumstances?

The NIA advocates for meeting the higher end of the fabric efficiency rating and incentivising social housing providers to complete all works at once. This is the most effective way to retrofit homes both in terms of cost and quality, and minimises disruption to residents. We would support enforcing the higher end of the range by 2033, in properties where this is cost effective and feasible to do so. This approach mitigates the risk of the target range disincentivising a best-practice, whole-house approach to retrofit in easier to treat properties where this is feasible. Flexibility and/or additional time could be granted in harder to treat properties where meeting the higher end of the range is not cost effective or feasible with the requirement to reach 120kWh/m2/year as a minimum.

For the minimum fabric efficiency standard, The NIA supports including solid wall insulation in the list of proposed measures. This is essential to make sure that solid wall homes are not left behind on the transition to net zero. For many solid wall properties, most or all of the measures on the proposed list will not be relevant, meaning that they will be subject to weaker energy efficiency standards. There is a risk that this will create a two-tiered society whereby those with solid walls will be subject to higher energy bills and colder homes than those without. Insulating solid wall homes will ensure that residents experience lower bills and higher levels of thermal comfort. It will also ensures that all of Scotland’s social housing sector is ready for the transition to clean heat. Further time could be given to insulate solid wall properties given the additional costs and complexities.

1 Department for Business, Energy and Industrial Strategy (2018). What are the Barriers to Retrofit in Social Housing? Available at: Barriers to retrofit in social housing (publishing.service.gov.uk)

To what extent do you agree that the new SHNZS should apply to mixed tenure properties?

Strongly agree

The NIA agrees the SHNZS should apply to mixed tenure properties and that more should be done to ensure that a higher proportion of mixed tenure properties are included. For example, rather than exempting properties in circumstances where social landlords share buildings with other tenures – if mixed tenure properties are unwilling or unable to contribute, funding streams, such as the Social Housing Net Zero Heat Fund, could include a percentage of funding allocated for ‘in-fill’ properties to mitigate this. This supports an area-based approach, allowing for economies of scale and addresses communities collectively.

To what extent do you agree that the new SHNZS should apply to Gypsy/traveller sites?

The NIA recognise that Gypsy/travellers have poorer outcomes than the settled population across a range of outcomes. These homes have been notoriously hard to treat within government funding streams due to a lack of clear guidance. To protect the most vulnerable residents, a solution must be found to include Gypsy/traveller sites in the SHNZS and further consultation should be sought on this.

What are your views on the timetable for introducing the new SHNZS?

Ensuring the required advice, guidance and support is in place in advance of standards being implemented is crucial to success. Therefore, the NIA accept the timetable for introducing the new SHNZS, to provide adequate time to consider enforcement, build resources and guidance and sufficiently consult and engage with a range of stakeholders. Timelines are already very tight, with minimum fabric efficiency standards due to come into force in 2028. Hence, it is critical that the Scottish Government implements the SHNZS as soon as possible to give social housing providers and the retrofit supply chain sufficient time to meet the regulations. Delays to this timeline would cause significant impact and hinder progress towards crucial net zero targets.

Summary – Scottish Government Heat in Buildings Proposals

Respondent Information Form

Please Note this form must be completed and returned with your response.

To find out how we handle your personal data, please see our privacy policy: https://www.gov.scot/privacy/

Are you responding as an individual or an organisation?  Organisation

Questionnaire

Question 1
To what extent do you support our proposal to prohibit the use of polluting heating systems in all buildings after 2045?

☒ Strongly support 

The NIA supports the prohibition of polluting systems in all buildings after 2045, as decarbonising Scotland’s buildings is essential for it meet its 2045 net zero target. This is supported by the proposed minimum energy efficiency standards (MEES), which will ensure that the majority of Scottish homes achieve a good level of fabric energy efficiency. However, the standards do not include more expensive measures such as solid wall insulation, which risks leaving some households behind.

A fabric first approach is vital to ensure that properties are ready for the transition to low-carbon heat. If heat pumps (or other low carbon heating systems) are installed in properties with inadequate insulation, there is a risk that those heat pumps will have overly expensive running costs, as heat pumps are most effective in properties with a high thermal efficiency. Making sure that a home has adequate insulation prior to installing a heat pump is essential to safeguard consumers from potential energy bill increases.

To improve information and advice, the NIA supports the development of an assessment tool to help building owners understand which types of clean heating system are most suitable for their building.

Question 2
To what extent do you agree that we should introduce a minimum energy efficiency standard to be met by private sector landlords by the end of 2028 (even if they are already using clean heating)?

☒ Strongly support 

The NIA supports the introduction MEES for private sector landlords by 2028, as private rented homes typically have a poorer standard of energy efficiency. The Scottish House Condition Survey published in May 2023 found that 30% of private rented sector households are fuel poor, in comparison, only 9% of those with a mortgage and 14% of those who own outright are assessed to be fuel poor – highlighting that private rented homes should be urgently addressed to protect tenants.

This said, there must be support in place to support landlords through the transition. A recent report by British Gas found that one of the main barriers for landlords looking to upgrade their properties is a lack of knowledge around EPC standards, with 44% of landlords not knowing the EPC rating of their properties. In addition, over half of landlords don’t know enough about the grants available to them to make improvements. Government and industry must work together to tackle the lack of knowledge and financial support to incentivise landlords to make changes to properties.

It is also important that private landlords are given sufficient notice before MEES come into force, so that they have time to upgrade their properties. Therefore, we would like to see the Scottish Government finalise MEES regulations and embed them into law as quickly as possible. This would provide much-needed clarity to landlords and the retrofit industry, which is important for targets to be deliverable. If MEES are implemented too close to the date they are set to come into force, it may be impossible to feasibly meet them. For instance, there may be a risk of supply chain bottlenecks if thousands of private landlords are trying to install energy efficiency measures at the same time.

The NIA agrees that MEES should still be met even if the property has clean heating installed. A fabric-first approach, in line with PAS 2035, should be followed and is essential to reduce overall energy demand and to improve the comfort and well-being of tenants.

(1 Scottish Government (2023). Scottish House Condition Survey: 2021 Key Findings. Available at: Fuel Poverty – Scottish House Condition Survey: 2021 Key Findings – gov.scot (www.gov.scot), 2 British Gas (2023). Greening the Private Rental Sector. Available at: british-gas-greening-the-prs-report.pdf (centrica.com)

Question 3
To what extent do you agree that we should introduce a minimum energy efficiency standard to be met in owner occupied homes (which still have a polluting heating system) by the end of 2033?

☒ Somewhat support 

The NIA supports the introduction of a MEES to be met in owner occupied homes by the end of 2033.

However, and especially without an initial legal requirement to do so, advice and support for owner occupiers must be improved to incentivise residents to make the necessary improvements to their homes. The proposal does state ‘there will be very strong incentives for homeowners to invest in energy efficiency’ however these are not fully realised within this consultation. We urge the Scottish Government to roll out these strong incentives as soon as possible, as these will be vital to encourage homeowners to meet MEES and to reduce the financial burden of doing so.

The NIA disagrees with the proposal that owner-occupied homes that have ended their use of polluting heating by 2033 will not be required to meet the MEES. Whilst we understand the need to protect homeowners from financial burden, it is vital to treat the fabric of the home first, in line with PAS 2035, to maximise efficiency of low carbon heat and to ensure measures deliver the intended outcomes. A fabric-first approach according to PAS 2035 is of critical importance for the following reasons:

• To protect residents from high energy prices. Low carbon heating system replacements are expected to be dominated by electrified options like heat pumps. The high electricity to gas price ratio (3.86 to 1 as of the January 2024 price cap level) means that without significant energy demand reduction measures, residents with electrified heating will be exposed to high energy bills. Therefore, we believe that households who have replaced polluting heating systems should still be subject to MEES. This is particularly important given the current cost-of-living and energy crises, with electricity prices expected to remain well above pre-crisis levels for the rest of the decade. MEES for all households, regardless of heating system, will protect them from the risk of sustained high energy bills in the long term.
• To increase the efficiency and reduce the running costs of heat pumps. The efficiency of heat pumps is linked to the fabric efficiency of homes. MEES for homes installing heat pumps are important because a higher fabric efficiency will increase the efficiency of heat pumps and reduce the cost they incur to run. Higher insulation standards should allow a smaller, cheaper heat pump to be installed that will have lower operating costs for residents. As such, MEES for all homes will result in more efficient and cheaper-to-run heating systems.
• To reduce the cost of electricity network expansion. If the majority of homes are to replace gas with electric heating, a huge expansion of the electricity grid will be required. There is a huge capital cost associated with building more renewable generation capacity and expanding the electricity network. According to Ofgem and the UK Government, £170bn – £210bn will need to be invested in the UK grid by 2050 to achieve our net zero targets. Therefore, it is imperative that homes consume as little electricity as possible because the cheapest energy is the energy we don’t use. Ambitious MEES which reduce the energy demand of new homes will reduce the scale by which the electricity network and additional renewable capacity will need to be expanded by, thus saving billions of pounds in capital costs for residents and government.

Therefore, the NIA believes that MEES should apply to all homes, including those with a non-polluting heating system. This should be accompanied by greater support for residents to improve the energy efficiency of their homes.

(3 Ofgem (2024). Energy price cap. Available at: Energy price cap | Ofgem, 4 Jillian Ambrose (2023). ‘Higher energy bills forecast for UK households next year’, The Guardian. Available at: Higher energy bills forecast for UK households next year | Energy bills | The Guardian, 5 Regen. Building a GB electricity network ready for net zero. Available at: Building a GB electricity network for net zero (regen.co.uk)

Question 4
Do you agree with our proposal to set a minimum energy efficiency standard that can be met by either installing a straightforward list of measures, or showing a good level of energy efficiency based on a reformed EPC fabric efficiency metric?

☒ Somewhat support 

The Scottish Government has recently consulted on EPC reform, therefore we expect the accuracy of EPCs will improve after the introduction of the new metrics that more accurately reflect the fabric efficiency of a home and support the transition to net zero. This will be further strengthened by the introduction of the Home Energy Model which will result in significantly more accurate and effective EPCs. EPCs take into account the individual property characteristics, whereas using a ‘one size fits all’ list that doesn’t consider property-specific characteristics creates a risk that the list of measures will become a ‘tick-box’ exercise that is irrelevant for certain property types.

It must be recognised and considered that properties have differing energy needs, and it is critical to ensure that residents have access to high quality, accessible advice to make sure that they can make informed choices about which measures are the most suitable for their property. The focus of the minimum energy efficiency standard must be to ensure that each property can benefit from the most suitable energy efficiency measures tailored to its individual needs.

Should the Scottish Government decide to use a list of measures to demonstrate compliance with the MEES, we believe that solid wall insulation (IWI and EWI) should also be included. This is essential to make sure that solid wall homes are not left behind on the transition to net zero. For many solid wall properties, most or all of the measures on the proposed list will not be relevant, meaning that these homes will be subject to weaker energy efficiency standards. There is a risk that this will create a two-tiered society whereby those with solid walls will be subject to higher energy bills and colder homes than those without.

The proposed requirements reflect a commitment to providing warmer homes and lower bills for residents. However, the practicalities for homeowners and landlords must be considered. Meeting the standards may involve a significant financial contribution, particularly in harder to treat properties which require complex measures. To alleviate this, the NIA recommends the implementation of additional support, funding and guidance to effectively deliver the proposed measures.

Question 5
What is your view on the initial proposed list of measures to meet the minimum energy efficiency standard?

☒ Somewhat oppose

We believe that solid wall insulation (IWI and EWI) should also be included on the proposed list of measures. This is essential to make sure that solid wall homes are not left behind on the transition to net zero. For many solid wall properties, most or all of the measures on the proposed list will not be relevant, meaning that these homes will be subject to weaker energy efficiency standards. There is a risk that this will create a two-tiered society whereby those with solid walls will be subject to higher energy bills and colder homes than those without.

Nearly a quarter of homes in Scotland have solid walls and of these, only 16% had insulated walls as of 2022. Hence, there is an urgent need for more targeted support for solid wall homes, particularly because 45% of a home’s heat can be lost through uninsulated solid walls. We recognise that installing solid wall insulation across all of the homes that need it will be a challenge and therefore we would be open to a later compliance date for solid wall properties. However, it is vital that solid wall properties are not disregarded altogether from MEES. This would leave residents of solid wall homes colder and worse off in the long-term. Therefore, solid wall insulation (IWI and EWI) installed in line with PAS 2030/2035 as part of a fabric first approach, should be included on the list of measures for any MEES. According to Energy Saving Trust, this could save a typical detached home £660 per year on their energy bills.

Early engagement with residents is also essential to demonstrate the benefits of such measures. Including higher cost measures in the list alongside providing high-quality advice will help residents to make informed choices. Where necessary, additional time and financial support to complete higher cost measures should be granted.

(6 Scottish Government (2024). Scottish House Condition Survey: 2022 Key Findings. Available at: Supporting documents – Scottish House Condition Survey: 2022 Key Findings – gov.scot (www.gov.scot), 7 Emma Spencer (2024). ‘Save energy with solid wall insulation’, Money Supermarket. Available at: Solid Wall Insulation | MoneySuperMarket, 8 Energy Saving Trust (2024). Solid wall insulation. Available at: Advice on insulating your solid walls – Energy Saving Trust)

Question 6
Do you think that properties for which most or all of the measures on the initial proposed list are not relevant should be required to meet an equivalent minimum energy efficiency standard?

☒ NO – these properties should be considered compliant once they have installed all the measures that are appropriate for their building type, even if this is few or no measures.
☒ YES – they should be required to meet the standard and additional measures should be included on the list (such as solid wall insulation, solid floor insulation and flat roof insulation), and they should be required to install all of these where feasible.
☒ YES – they should be required to meet the standard and additional measures should be included on the list (such as solid wall insulation, solid floor insulation and flat roof insulation), but they should only be required to install some of these where feasible and cost effective.
☒ YES – they should be required to meet the standard and additional measures should be included on the list (such as solid wall insulation, solid floor insulation and flat roof insulation), but they should only be required to install some of these where feasible, and they should be allowed additional time to do so.

Question 7
Do you think that properties for which most or all of the measures on the initial proposed list are not relevant should be required to meet an equivalent minimum energy efficiency standard?

☒ DON’T KNOW – The NIA believe that both the worst first and fabric first approach should be followed to address the need for investment in existing homes. MEES across housing tenures are a key regulatory lever that will drive progress towards more energy efficient housing.

However, the enforcement of private sector MEES and incentivising owner occupier MEES must be considered to ensure residents and landlords are motivated to make energy efficiency improvements. Measures must remain affordable, fair and feasible for homeowners and landlords and the Scottish Government should ensure that advice and financial support is accessible.

In terms of approach, the standard suggests that evidence including invoices or photographs could be used to show that a property has installed all of the measures (or as many as are feasible) for it to meet the standard. However, reformed EPCs will also include all the information that is required to show that an owner has met the standard. The NIA strongly advocates for robust evaluation and quality control of measures installed under MEES (such as through in-use performance testing) to avoid exposing residents to property damage and health risks, such as damp and mould, resulting from poor quality installations. High quality, PAS-compliant installs must be promoted to ensure that the benefits of measures are delivered as intended.

Question 9
To what extent do you support the requirement to end the use of polluting heating following a property purchase?

☒ Neither support nor oppose – The NIA agree that to ensure we reach climate change targets, we should consider other options to influence homeowners, landlords and businesses to make the change to clean heating systems before 2045.

The cost of upgrades to meet requirements will be a significant challenge for homeowners, especially for first-time buyers – and would significantly impact the housing market; affecting property values and impacting the buying/selling process. Lower-income homeowners are likely to be impacted the most, and this could create disparities in housing options.

Importantly, whilst the requirement to end the use of polluting heating is necessary, it is vital to ensure that properties are first ready for the transition to low-carbon heat. If heat pumps (or other low carbon heating systems) are installed in properties with inadequate insulation, there is a risk that those heat pumps will have overly expensive running costs, as heat pumps are most effective in properties with a high thermal efficiency. Making sure that a home has adequate insulation prior to installing a heat pump is essential to safeguard consumers from potential energy bill increases.

The NIA agrees that a grace period should be implemented to allow homeowners to make required changes. In order for the requirement to be fair, the Scottish Government would need to ensure:

• There are robust enforcement procedures in place to monitor and verify that upgrades have been installed to a high standard
• There is a significant range of finance products/ public funding to support people and businesses to make the required upgrades, including those who might not currently be able to access standard forms of private finance, such as mortgages.
• Homeowners have access to comprehensive advice and information services
• That the impact on the housing market is minimised as much as possible – for example providing an exemption for first-time buyers

Question 11
To what extent do you support our proposal to apply a cost-cap where people are required to end their use of polluting heating following a property purchase?

☒ Neither support nor oppose – The NIA understands the rationale for implementing a cost-cap to ensure homeowners do not pay unreasonable costs and that financing options can be determined.

However, introducing a cost-cap can be problematic as it could lead to unintended consequences such as compromising quality and market distortion. A strict cost-cap may influence selection of measures based solely on cost, rather than considering the most effective and sustainable solution – this could also discourage innovation in the sector. For instance, a low cost cap may exclude measures like solid wall insulation which are higher cost but which have significant benefits in terms of energy bill savings and thermal comfort.

If a cost-cap is implemented, the NIA recommends that the cap is flexible and adaptable to account for factors such as inflation, changing market rates and harder to treat properties.

Question 12
To what extent do you support our proposal to apply a cost-cap where people are required to end their use of polluting heating following a property purchase?

☒ Another, please suggest below – The three options proposed each have disadvantages which have been highlighted in the consultation. If a cost-cap is implemented, the NIA recommends that the cap is flexible and adaptable to account for factors such as inflation, changing market rates and harder to treat properties. To provide flexibility and fairness, cost-caps should take a range of variables into account, including building type, wall type, EPC rating, heating type etc, as seen with other energy efficiency schemes. Every property is different and there are many factors that can affect the cost of upgrading to a reasonable level of energy efficiency. Therefore, it is important that any cost cap reflects the heterogenous nature of Scotland’s housing stock and does not exclude harder to treat properties from important energy efficiency standards.

Question 18
We will need to have a way to monitor if people are meeting the Heat in Buildings Standard, and discussed two options for this. Which do you support?

☒ A combination of the two  – The NIA supports using a combination of both EPCs and sampling to monitor and enforce the proposed requirements.

The NIA also strongly advocates for evaluation and quality control of measures installed, to avoid exposing residents to property damage and health risks, such as damp and mould, resulting from poor quality installations. Monitoring must take into account the quality of installs to ensure that the intended consequences are delivered. These further checks could be completed as part of the sampling process.

Question 19
We will need to have a way to enforce the Heat in Buildings Standard. We discussed possible options to help achieve compliance. What are your views on these ideas?

☒ I support a mixture of the above options – The NIA believes the most effective way to enforce the Heat in Buildings Standard is through proactive reinforcement; offering comprehensive information and advice alongside a range of different financing options. The Scottish Government’s priority must be to provide residents with financial support and generous incentives to help them comply with MEES, with penalties a last resort.

The NIA agrees with proposing that private landlords should be subject to civil penalties if they refuse to meet the MEES. However, a recent report by British Gas shows that lack of information and costs are the main barriers for landlords when considering upgrades to properties. Therefore, it is important that appropriate support is available to help landlords comply and to avoid the need for penalties wherever possible.

For homeowners, the NIA agrees with the Scottish Government’s decision to avoid wider civil penalties, at least for the initial stages of the standard – particularly as the main barrier is the cost of measures. Homeowners should be engaged as early as possible to achieve targets. Information and support around eligible funding streams must be improved to incentivise homeowners to implement measures.

In addition, it is likely that enforcement bodies will experience gaps and inconsistencies with the quality of EPC data, hindering the identification of target properties. The Scottish Government should facilitate cross-team working for example between landlords, local authorities, Historic Environment Scotland, building control and trading standards to share intelligence and coordinate enforcement activity.

(9 British Gas (2023). Greening the Private Rental Sector. Available at: british-gas-greening-the-prs-report.pdf (centrica.com), 10 Centre for Sustainable Energy (2022). Compliance & Enforcement of the Minimum Energy Efficiency Standard (MEES) in the Private Rented Sector. Available at: Compliance & Enforcement of the Minimum Energy Efficiency Standard (MEES) in the Private Rented Sector (centreforsustainableenergy.ams3.digitaloceanspaces.com)

Question 20
To what extent do you support our proposals to modify the Standard or exempt certain people from the need to meet the Heat in Buildings Standard?

☒ Somewhat support – The NIA accepts that individual circumstances, and our homes and buildings, vary significantly, and therefore any enforcement should be fair and should protect vulnerable residents. Exemptions should be treated on a case-by-case basis where possible to allow for the greatest flexibility.

As full exemption from standards would hinder the pace we reduce carbon emissions, this should only be provided in a very limited set of circumstances where it is not possible for standards to be met. Instead, additional time and support should be offered for properties where it is more difficult to meet standards. For instance, we would support giving solid wall homes a later date to comply with MEES. This recognises the challenges associated with insulating Scotland’s solid wall housing stock, without excluding them from standards altogether, which would leave residents of solid wall homes colder and worse off.

Question 22
To what extent do you support our proposals to give certain people extra time to meet the Heat in Buildings Standard?

☒ Somewhat support – The NIA accepts that individual circumstances, and our homes and buildings, vary significantly, and therefore any enforcement should be fair and should protect vulnerable residents.

The NIA also agrees that extra time may be required for those living in properties where clean heating options are limited – in this case residents should focus on improving the fabric of the building to reduce energy demand and to ensure the property is ready for clean heat once suitable options become available.

As full exemption from standards would hinder the pace we reduce carbon emissions – additional time and support should instead be offered, where reasonable and feasible, to do so.