The Government has confirmed that both Standard Assessment Procedure (SAP 10.3) and the Home Energy Model (HEM) will be used to calculate compliance with the Future Homes Standard (FHS) as part of a phased transition for new build homes.

Elmhurst has been closely involved in the discussions with both the Ministry of Housing, Communities & Local Government (MHCLG) and the Department for Energy Security and Net Zero (DESNZ). We welcome this confirmation and are pleased that the government has opted for a pragmatic approach that supports a smoother implementation of FHS for England’s house-building sector.

When the Future Homes Standard consultation launched in 2023, it was expected that the Home Energy Model (HEM)—with a tailored Future Homes Standard wrapper—would be the sole compliance tool. However, following feedback from industry the government has opted to allow a new updated SAP 10.3 version to be used as an interim methodology. It will feature a new notional dwelling, updated carbon and primary energy factors, and refinements to the current SAP 10 to support compliance with the Future Homes Standard. Thus ensuring more energy efficient homes will be delivered.

In short, this means both SAP 10.3 and HEM can be used during a phased transition- the timelines of which will become clearer once the Future Homes Standard regulations are laid before Parliament.

By continuing to use the well-established SAP 10 alongside the gradual rollout of HEM, the government aims to ensure a smoother shift once HEM and its supporting systems are fully ready.

What This Means for OCDEAs

For On Construction Domestic Energy Assessors (OCDEAs), the continuation of Design SAP 10 will offer a familiar and reliable method for assessing compliance during the transition period. Having used SAP 10 for several years, assessors will benefit from a reduced learning curve and greater consistency in their work.

Elmhurst’s Design SAP 10 software will soon be updated to support assessments under both Part L 2021 and the Future Homes Standard, and we will be releasing all the necessary guidance and giving access to training/CPD sessions to ensure assessors understand how to apply it effectively.

What This Means for Builders

The dual-methodology approach significantly reduces the risk of delays and compliance uncertainty for builders. The Future Homes Standard wrapper for HEM is expected to require more detailed input from builders to assessors. In the absence of formal conventions guiding the handling of missing data, this could have resulted in project delays. Allowing the use of SAP 10.3 mitigates these risks by maintaining a familiar and well-established compliance route.

Elmhurst’s New Build Residential Manager, Jason Hewins, welcomes this update from the government:

“We are pleased that Government has now confirmed the methodologies to be used for calculating compliance with the Future Homes Standard. This long-awaited clarity is crucial—not just for Elmhurst, but for the whole industry—as it allows us to move forward with confidence.

We will be progressing development of our software (both SAP 10.3 and HEM), releasing tailored training, and providing clear, accurate guidance to our members and clients. As an independent and trusted accreditation scheme we are committed to supporting assessors, builders, and wider stakeholders through this period of change.”

Elmhurst will continue to work with government as well as our own members and industry stakeholders, to ensure the successful roll out of FHS. While this announcement brings more clarity, more detail is still needed—particularly in relation to transitional support and timelines.

We will continue to update our members and clients with further announcements, including guidance, training opportunities and software release timelines for both SAP 10.3 and the Home Energy Model.

Related Links

https://www.gov.uk/guidance/standard-assessment-procedure