SAP 10.3 and the Home Energy Model
A dedicated place to explain SAP 10.3 and the Home Energy Model accurately, with technical review and official references.
What is approved now?
The government’s Standard Assessment Procedure guidance says SAP 10.3 is currently the sole approved methodology for Future Homes Standard compliance. The Home Energy Model (HEM) did not launch alongside the standard; government plans to introduce it alongside SAP 10.3. Check the official guidance before starting a live submission because this position may change.
What information does an assessor need?
Plans and specifications for geometry, fabric, glazing, ventilation, heating and renewable systems are more useful than a floor area alone. If decisions are still open, make assumptions explicit and update the assessment as the design progresses. An as-built check must reflect the actual specification.
Non-domestic buildings use a different calculation methodology. Tell us about commercial or mixed-use areas so UKSAPS can confirm the appropriate assessment scope. This website is aimed at new-build SAP work, not existing-home RdSAP surveys.
Source: GOV.UK Standard Assessment Procedure, checked 21 October 2026. Technical sign-off pending.