HEM Consultation - Government Response Published

A quick reminder, the HEM consultation was separate to the FHS consultation and focused on the design and function of the replacement to SAP and was accompanied by a consultation version of the HEM software to help inform feedback.



For those that have been following the ‘Energy Calculation as a Service’ (ECaaS) updates over the last months no surprises are expected. For those less closely involved, but still interested in detail, the consultation response provides a handy summary of the decisions the government has made since the consultation closed.

A few very high level takeaways include:

• HEM is not an evolution of SAP, it is a whole new model
• Confirmed it will be called the Home Energy Model (HEM) and the calculation will be undertaken centrally with the ‘Schemes’ providing front-end software for Assessors
• Based on British and EU standards for the calculations
• 30-minute time step resolution is confirmed
• They are continuing to test and validate the model
• A greater number of product categories are included compared with SAP, eg cylinders (and products that were in SAP Appendix Q are being included in the main model)
• There will be an updated version of the ‘Appendix Q’ procedure for enabling the inclusion of new products into the model
• Since consultation:
• Ventilation and infiltration reworked
• Updated storage heater and heat battery models
• Expanded types of heat pumps included
• Reworked solar PV and electric battery models
• Improved the hot water demand and storage

The Hub, via its HEM and Notional Building Implementation Group, continues to work with government officials to prepare the ground for the successful implementation of the Future Homes Standard. This said, we all eagerly await the FHS publication.

By David Adams