What is the SAP calculation, and what is it used for?
The Government Standard Assessment Procedure (SAP)
SAP is the Government’s Standard Assessment Procedure for the calculation of predicted energy use and resulting carbon dioxide emissions from a dwelling. It is used as the main compliance tool for Building Regulations Part L1A, to satisfy Criterion 1 and provides information to satisfy Criterion 2 and Criterion 3. It is also used to produce the Energy Performance Certificate (EPC) for the completed dwelling.
The SAP calculation is based on the energy balance of the dwelling over the course of a year taking into account a range of factors that contribute to energy efficiency, and is based on a standardised occupancy profile.
The SAP calculation is undertaken via approved software packages and is used to provide the following information for a new dwelling:
+ The Target Emissions Rate (TER)
+ The Target Fabric Energy Efficiency (TFEE)
+ The Dwelling Emissions Rate (DER)
+ The Dwelling Fabric Energy Efficiency (DFEE)
+ The SAP rating
+ The Environmental Impact Rating
Building Regulations Approved Document Part L1A gives guidance as to how to reasonably demonstrate to Building Control that a building has been designed and constructed in compliance with the appropriate energy efficiency requirements of for new-build dwellings. Additional industry produced guidance is available, for example NHBC Foundation ‘Part L 2013–Where to Start’ guides, NF58 and NF59.
A SAP assessment is carried out at two stages in the design and construction of a new dwelling:
+ At Design Stage, with a submission to Building Control before work starts on site
+ At As Built Stage, with a final submission on completion of the dwelling
The two submissions can be used by Building Control to check compliance with required targets. A clear connection must be evident between product specifications and the data inputs into the SAP software. The As Built submission is required to produce the EPC for the completed dwelling.