The Government took the decision in May 2025 to make SAP 10.3 available for use with the Future Homes Standard (FHS) as an alternative to the Home Energy Model (HEM), according to its response to the 2023 Future Homes and Buildings Standards consultation1. The decision was taken and communicated alongside the wider package of standards, which the Government intends will come into force on 24 March 2027 for non-higher-risk building work, followed by a 12-month transition period1.
The consultation on the Future Homes Standard was published in December 2023 and closed in March 2024, drawing 2,421 responses, of which eight email submissions were excluded as out of scope, leaving 2,413 included in the final analysis1. The Government's response states:
"In May 2025, the Government therefore took and communicated the decision to make available for use with the FHS an updated version of SAP, known as SAP 10.3, which will be approved for use as an alternative to HEM"
The response confirms that the existing performance metrics will be retained: Target Emissions Rate (TER), Target Primary Energy Rate (TPER) and Fabric Energy Efficiency (FEE) for dwellings, and TER and TPER for non-domestic buildings1. Delivered energy will be introduced as a voluntary reporting metric for new dwellings, reported through the BREL report where HEM is used1.
On the fabric and services of the dwelling notional building, the Government has set these as presented in Option 1 at consultation, but with a different approach to solar provision, and has created a new functional requirement for renewable electricity generation for new dwellings and buildings containing dwellings1. For dwellings connected to heat networks, compliance will use the heat network approach, including comparison against a standardised low carbon heat network notional building for communal networks and a revised sleeving route for district networks1. The Option 1 and Option 2 distinction remains the reference point for how the notional dwelling is set.
Other confirmed changes include raising the maximum specific fan power for continuous dMEV systems to 3.5 W/l.s and lowering the minimum SEER for comfort cooling to 4.61. The Government has proceeded with fixing operational and maintenance information to heat pumps, despite 54.2% of respondents to Question 16 saying they did not believe the draft Approved Document's operating and maintenance information was adequate1. It has decided not to proceed with the proposed revision to guidance on sizing hot water vessels, and not to change the expected standards from those in the 2021 Approved Document for buildings with low energy demand that are not exempt from the Building Regulations1.
Why it matters for households
The choice of calculation method determines how a new home's energy performance is demonstrated at the design stage, and therefore what fabric, heating and ventilation specification is built into it. A home assessed under SAP 10.3 rather than HEM may be modelled differently, but the underlying standards it must meet are the same set of metrics: TER, TPER and FEE1. For a householder, the practical effect is on the running costs and comfort of a home once occupied, not on the compliance route taken on paper. The heating specification in a new home under the FHS is expected to be low carbon, and the standards are intended so that homes built to them will not require retrofitting to become zero carbon in use once the electricity grid is fully decarbonised1. Households in homes created through a material change of use will see current limiting standards retained, with updated guidance to help ensure Home User Guides are provided to those owners1.
What happens next
The amending regulations will come into force for higher-risk building work, including a stage of HRB work or work to an existing HRB, on 24 September 20271. To continue building any remaining dwellings or a particular building to the 2010 standards, work must be started before 24 March 20281. The Government has said it will publish a call for evidence and consider research on the energy performance gap and building performance evaluation, and plans a further consultation on energy efficiency standards for dwellings created through material change of use1. It has decided not to proceed with a Future Homes Standard brand1.
Sources1 cited
- The Future Homes and Buildings Standards: 2023 consultation response, assets.publishing.service.gov.uk