SAP
Calculations

What are SAP calculations?

SAP (Standard Assessment Procedure) is the government-approved methodology used to calculate the energy performance of new dwellings in England for Building Regulations purposes. SAP can also be used for some work to existing dwellings, including as an alternative compliance approach for certain extensions. For new dwellings in England, SAP is used to assess the dwelling against the applicable energy performance requirements of Part L of the Building Regulations. For new dwellings, the relevant design-stage calculations and specification information are provided to building control before work starts. The calculation is updated at completion using information for the dwelling as constructed, and a new-build EPC is required once construction is complete.

Why are SAP calculations necessary?

For a new dwelling, the SAP assessment provides the calculations used to demonstrate whether the design meets the applicable Part L energy performance targets. The calculations form part of the information used for the Building Regulations compliance process, can avoid costly delays, and keep your project on schedule. Good SAP results can also make your property more attractive to buyers or tenants. For developers, architects, and builders, a quick, accurate SAP assessment saves time and money, reduces compliance risk, and protects your reputation.

When do you need a SAP calculation?

• Design stage: For a new dwelling, the design-stage calculation is completed before work starts. The relevant calculated rates and the specification used in the calculation are provided to the building control body before work begins.
• As-built stage: For a new dwelling, the SAP calculation is updated at completion using the dwelling as constructed, including relevant changes made during construction and the measured air permeability. A new-build EPC is also required on completion.