Standard Assessment Procedure


A SAP calculation is an energy rating, which provides results of CO2 emissions and fuel costs for a new dwelling and for conversions, renovations and extensions. SAP calculations must be carried out at the design stage prior to the commencement of works on site, and also at the completed “as-built” stage.

All new buildings will need to be assessed under the new Part L1A 2013 or Part L1B for existing. The Design SAP refers to the DER/TER (Dwelling Emission Rate/Target Emission Rate) Calculations. Using the plans and specification provided by the architect we will calculate the thermal performance of each building element. Thermal performance is expressed as 'U' values (the rate at which heat passes through the fabric of the building), the higher the 'U' value the greater the rate of heat loss. Using SAP compliant software we will input the building design and specification details. This software determines whether the proposed dwelling will meet the requirements of the Building Regulations with regards to the conservation of fuel and power.

What is an As Built SAP?

The As Built SAP calculations are used to generate the EPC. However, If you have made any changes to the original design/ specification e.g. layout, materials used, air tightness test result etc. building control may request detailed As Built SAP report to ensure that the dwelling still falls within the “pass rate” energy rating. We will generate a new SAP calculation to reflect the results of the air tightness test and any variations to the original specification. On completion we will upload this data to the governments Domestic Central Register – Landmark.


(EPC)? An Energy Performance Certificate (EPC) provides potential buyers and tenants with an indication of the energy efficiency of a property. The certificate will contain information about the property’s typical energy costs and will recommend ways to reduce energy use to make the property more energy efficient. First introduced in 2007 as part of the now-abolished Home Information Pack, an energy performance rating is necessary for properties being sold or rented in England, Wales and Northern Ireland.

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