SAP for New Build

New build homes in England and Wales must satisfy three compliance metrics under Part L1A of the Building Regulations: a Target Emission Rate (TER) for carbon dioxide, a Target Fabric Energy Efficiency (TFEE) rate, and minimum fabric standards covering wall, roof, floor and window U-values. The SAP calculation – the Standard Assessment Procedure – is the approved methodology for demonstrating compliance with all three. House builders, architects and self-builders commission SAP calculations at design stage and at completion, and Build Energy’s accredited assessors handle both reports required under Part L.

Every new dwelling in England and Wales requires two separate SAP calculations. The first – the Predicted Energy Assessment (PEA) – is produced from the design drawings before construction begins and submitted to building control as part of the Building Regulations application. The second – the as-built SAP – is produced after completion using the confirmed specification and is used to generate the Energy Performance Certificate (EPC), which must be lodged on the EPC register before practical completion.

The SAP calculation checks three things for every new dwelling. First, the Target Emission Rate (TER) – the maximum allowable carbon dioxide emission rate. Second, the Target Fabric Energy Efficiency (TFEE) – the maximum allowable energy demand from the building fabric. Third, minimum fabric performance standards: limiting U-values for walls, roofs, floors and windows that must not be exceeded regardless of the overall SAP score. All three must be met before building control can issue a completion certificate. For more detail on DER and TER compliance see our DER and TER guide.

A draft specification at RIBA Stage 2 is sufficient to run a preliminary design-stage SAP. Build Energy typically needs floor plans and elevations with dimensions, the proposed construction specification (wall, roof and floor U-values), window and door specifications with orientation, heating system details, hot water provision, and any renewable energy measures. If the specification changes during design development, revisions can be turned around quickly. For background on the wider SAP framework, see what SAP calculations involve.

When do I need to submit SAP calculations for a new build?

A Predicted Energy Assessment (PEA) must be submitted to building control at design stage, before any construction begins. The as-built SAP calculation and EPC must be lodged on completion. Build Energy handles both stages.

What does Part L1A require for new build homes?

Part L1A sets targets for the carbon dioxide emission rate, fabric energy efficiency and the minimum fabric standards (U-values). New homes must meet all three compliance metrics. The specific targets depend on the version of Part L applicable when building regulations approval was sought.

What is a Predicted Energy Assessment?

A Predicted Energy Assessment (PEA) is the design-stage SAP calculation submitted to building control before construction starts. It demonstrates that the proposed design will meet Part L requirements. It is not an EPC – the final EPC is produced from the as-built calculation.

Does the SAP calculation need to be updated if the design changes?

Yes. If significant changes are made to the specification – such as the heating system, insulation levels, or window specifications – the SAP calculation should be updated to confirm the revised design still meets Part L. Build Energy can provide revisions quickly when changes are confirmed.

What information does Build Energy need for a new build SAP?

We typically need floor plans and elevations with dimensions, the construction specification (wall, roof and floor U-values), window and door specifications with orientation, heating system details, hot water provision, and any renewable energy measures. A draft specification at RIBA Stage 2 is sufficient to start.