Understanding Part L
The Standard Assessment Procedure (SAP) demonstrates compliance with Part L of the Building Regulations for new dwellings and conversions. It also underpins the Energy Performance Certificate (EPC) issued at completion.
Basics
A SAP calculation is used to demonstrate compliance with Part L. For new build properties it produces a Building Regulations Compliance Report and a SAP Worksheet. As part of the process, the building receives: a Target Emissions Rate (TER) and a Target Fabric Energy Efficiency (TFEE), and we then calculate the building’s Dwelling Emission Rate (DER) and Dwelling Fabric Energy Efficiency (DFEE).
SAP results also provide the data to produce an EPC (rating A–G) once the dwelling is built and the As-Built SAP is finalised.
Coverage
Yes. A SAP assessment must be completed on all new build properties to gauge energy efficiency. On large developments with repeated house types, a sample assessment can be applied across identical plots—so every plot has a SAP, without re-assessing each one.
Checklist
Improve your score
The SAP calculation measures the dwelling’s energy performance. By generating and retaining heat more efficiently, the score improves. SAP is also linked to government targets for reducing emissions through dwellings.
An Energy Performance Certificate shows a property’s performance as a rating (A–G). It’s produced from the final, As-Built SAP calculation once construction is complete.
After the As-Built SAP is finalised and lodged on the register, an EPC is issued for the dwelling.
Send your drawings and spec—we’ll advise the clearest, most cost-effective route to compliance.