New energy model to replace SAP

New standards to bring UK in line with international best practice

Homes on building site

Credit: - Shank_ali

The government is proposing to replace the Standard Assessment Procedure (SAP) with a new Home Energy Model (HEM), to coincide with the introduction of the Future Homes and Buildings Standards and bring the UK’s energy modelling standards in line with international best practice.

SAP is used to calculate compliance with Part L of the Building Regulations in England. It would be replaced by the HEM: Future Homes Standard (FHS) in 2025, to demonstrate that dwellings comply with the FHS. The model is still under development, but the government is consulting on it ‘while it is still at a formative stage’ so that industry can participate in the development process.

According to Elmhurst Energy, the UK’s largest accreditation scheme for energy assessors, the Home Energy Model would eventually be expanded to include production of Energy Performance Certificates. Stuart Fairlie, Elmhurst’s MD, said: ‘HEM should not be seen as a replacement for SAP, but rather an enhancement to support the transition to net zero.’ 

Changes to the model ecosystem include an open-source methodology and a revised database of product characteristics, while the calculation methodology includes increased time resolution.