What is SAP?

Standard Assessment Procedure (SAP) is a method for calculating the CO2 emmisions of dwellings. SAP calculation is required for all new domestic buildings and some extensions and conversions to demonstrate compliance with the Building Regulations Part L1.

Using an approved SAP software, the CO2 emission of a domestic building can be calculated based on the building specifications. This CO2 emission is called the Dwelling Emission Rate (DER). For a building to be compliant with the regulations, the DER must not be greater than the TER (Target Emission Rate).

There is also a requirement for the dwelling fabric efficiency to meet building regulations standards which means that Dwelling Fabric Energy Efficiency (DFEE) should be lower than that Target Fabric Energy Efficiency (TFEE).

SAP calculation is done in two stages - at the design stage and the built stage. The SAP method is also used to calculate the EPCs for the dwelling .

Design Stage SAP & Predicted EPC

Before commencement of building work, a SAP calcuation should be carried out to demonstrate that the Dwelling Emission Rate will be no worse than the Target Emission Rate. The design stage SAP compliance document and Predicted EPC will be provided to you upon completion of the SAP calculations. This enables you to demonstrate to your the building control body that the proposed dwelling will comply with the regulations.

Built Stage SAP & EPC

On completion of building work, another SAP calculation referred to as 'As Built' calculations should be carried out based on the actual building specifications i.e. incorporating any specification changes from the design stage. You will be provided with built stage SAP compliance document and an Energy Performance Certificate. These enable you to demonstrate to your building control body that the dwelling - as built - complies with the regulations.

SAP & EPC for Conversions & Extensions

As well as new builds, we provide SAP & EPC calculations for Conversions and Extensions


At Energaia, we carry out SAP calculations and provide reports that demonstrate that the upgraded elements of your conversion are compliant with the requirements of Part L1B.


We can also carry calculations and provide reports to show that your extension complies with Part L1B of the building regs. To do this, we carry out two calculations: one with your proposed specifications and another with specification limits in Part L1B.

New Build

We provide SAP & EPC Calculations for new builds. If for any reason, you require EPC only for a new build, we can help with that too.

Our Qualifications

We are qualified and accredited to carry out SAP and EPC assessments. The compliance documents and certificates we issue are acceptable to all building control officers.

We are accredited with Stroma to carry out SAP and EPC.

Stroma Certified

We have ABBE Certification to carry SAP and EPC.

ABBE Certified

Please call us now to discuss your requirements.

Our other services

Air Permeability Testing

Air Permeability Testing or air pressure testing for Commercial and Residential properties.

SBEM for Commercial Buildings

SBEM calculations to demonstrate compliance with Part L2 of the building regulations.

EPC for Commercial Buildings

Energy Performance Certificates for all non-domestic buildings of any complexity.

Water Efficiency Calculations

Water Efficiency Calculations for compliance with Part G of the building regs.

EPC for Domestic Buildings

Energy Performance Certificates for all new domestic buildings of any size.

Energy Efficiency Consultancy

Consultancy to help you comply with energy efficiency requirements of building regs.