You will require a SAP calculation if you are doing one of the following:  

• •  Building a new dwelling  

• •  Converting a building via change of use into a domestic dwelling  

•  Building an extension where any new glazing is more than 25% of the new floor area 

ATSPACE SAP assessors are fully accredited to help you achieve compliance in all the above types of SAP calculations. All ATSPACE’s SAP assessors are also qualified domestic energy assessors, so they are qualified to also produce the final EPC (Energy Performance Certificate).  

A SAP calculation is the energy calculation on a domestic dwelling required by Part L of the building regulations. Part L1A relates to new build properties, and Part L1B relates to existing buildings, conversions and extensions.  

The SAP calculation calculates the total amount of CO2 (carbon dioxide) that the property produces.  

SAP stands for Standard Assessment Procedure and is the approved method for calculating the energy performance of a domestic dwelling. The SAP calculation is divided into separate sections for each element. Each element has stand-alone targets, with the individual and total sum creating the final result.  

The SAP assessment is a desk top calculation and is carried out from a set of drawings and specifications provided by the client. The SAP calculation for a new build property has two stages: the design stage SAP and the As Built SAP.  

• •  The design stage SAP is carried out before the build is started, usually at the planning stage. A PEA (Predicted Energy Assessment) is        produced. 

• •  The As Built SAP is as it sounds and is completed once the property has been built. The As Built SAP is an amended version of the           Design stage SAP, but includes the actual products used rather than what is proposed. The As Built SAP also includes the air test               result, rather than the target. 

• •  Conversion SAP calculations must show efficiency standards and meet carbon standards. The process is similar to the new build, but       the calculation is different, and only one calculation is carried out.

• •  Extension SAP Calculations require that the extension does not have more than 25% of the new floor area as new glazing. This is to           show that the extension doesn’t make the existing property worse than it currently is with regard to solar gains. For this type of SAP         calculation, you need to compare the existing building with the proposed building.