SAP10 Calculations
For New Builds

New Build Residential (Part L1)

As of the 15th June 2022 Part L1 2021 requires all new domestic dwellings to prepare a SAP10 calculation in order to demonstrate that the dwelling’s energy emission rate (DER) is lower than a target emission rate (TER). This is also sometimes referred to as an energy report. The process involves a set of desktop calculations prepared using drawings and specifications. Part L requires that the SAP calculation must been submitted to the building control officer prior to commencement of any works onsite.

For further information about the new SAP10 methodolgy and the the 2021 Regulations and the changes its likely to have on new projects, visit our 2021 Building Regulations Page for further information and guidance.

Our experienced team of SAP accredited energy assessors are able to work with you to ensure that your project not only passes the DER/TER requirement but does so in the most cost effective manner possible. Our approach for every project is to provide a bespoke solution customised for every client and their project. Our solutions have helped clients save many thousands of pounds which has forged long lasting relationships.

All Design Stage SAP Calculations include a Predicted Energy Assessment (PEA) which is required for marketing and selling a dwelling off plan.


Upon completion of a dwelling and confirmation of the actual build specification the "As Built" SAP calculation is produced which is then used to prepare the Energy Performance Certificate (EPC) for the dwelling.

Don't forget! Use our New Build Pack service to save money and hassle by combining your SAP, EPC, Air Permeability Testing, Extract Ventilation Testing, Water Efficiency Calculation and Acoustic Testing (if applicable) all together.

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Conversion Projects (Part L1 2021)

Under Part L1 2021 of the building regulations you are required to provide a SAP calculations when converting an existing non-domestic building into a residential property. This is commonly known as "change of use". Typical scenarios include barn conversions, converting offices, shops and any other commercial building into a residential property.

The purpose of the SAP calculation is to demonstrate that the existing buildings insulation will provide adequate thermal properties to the occupants where previously the building use didn't require. Typically in barn conversions this may require the existing walls, floors and roofs to be insulated. For existing shops and offices this may require little to no changes in the insulation dependant on the age and construction of the building.


The requirements for conversion project aren't a strict as new build standards and allow for existing elements of the building to be incorporated into the design.

Upon completion of a dwelling the SAP calculation is used to prepare the Energy Performance Certificate (EPC).

Why Use BEAT?

  • Free Standard U-Value calculations (upgrade to BRE BR 497 U-Values click here)

  • Free summer overheating risk analysis

  • Experienced and qualified assessors providing bespoke low cost solutions saving you money and time

  • Fast turnaround

  • Detailed reports and checklists in pdf format

  • A dedicated assessor from start to finish

Frequently Asked Questions