The Standard Assessment Procedure (SAP) is the UK Government’s methodology for assessing and comparing the energy and environmental performance of residential buildings. It is a key requirement for demonstrating compliance with Part L of the Building Regulations and forms the basis of the Energy Performance Certificate (EPC).
What is a SAP Calculation?
A SAP calculation evaluates the energy performance of a dwelling based on factors such as:
- Building fabric (walls, floors, roofs, insulation levels)
- Heating and hot water systems
- Ventilation and air tightness
- Lighting efficiency
- Renewable and low-carbon technologies
Using this information, SAP generates key performance metrics including:
- Dwelling Emission Rate (DER)
- Target Emission Rate (TER)
- Dwelling Fabric Energy Efficiency (DFEE)
- Target Fabric Energy Efficiency (TFEE)
To comply with Building Regulations, the calculated performance of the proposed dwelling must meet or improve upon the target values set by the notional building.
Stages of the SAP Process
1) Design Stage (SAP Assessment)
At the planning or design phase, SAP calculations are carried out based on proposed drawings and specifications. This stage is used to:
- Demonstrate compliance with Part L
- Identify if design improvements are required
- Produce a Predicted Energy Assessment (PEA), which is required for marketing new dwellings
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2) As-Built Stage (SAP Calculation & EPC)
Once construction is complete, the SAP calculation is updated to reflect the “as-built” dwelling. This includes confirmed specifications, air pressure test results, and any changes during construction.From this final SAP assessment, the Energy Performance Certificate (EPC) is generated. The EPC:
- Provides an energy efficiency rating from A (most efficient) to G (least efficient)
- Includes estimated energy costs
- Recommends potential improvements
What is an EPC?
An EPC is a legal requirement when a dwelling is built, sold, or rented. It summarises the energy performance of the property in a format that is easy to understand for owners, tenants, and buyers
For non-domestic buildings, the EPC provides an energy efficiency rating from A+ (most efficient) to G (least efficient). It also includes:
- Asset-based energy performance indicators
- Estimated energy consumption and carbon emissions
- Recommendations for improving efficiency
Our Approach
We provide end-to-end SAP and EPC services, working closely with design teams and contractors to ensure compliance is achieved efficiently. Our focus is on identifying cost-effective improvements early, minimising redesign, and delivering a smooth path to certification.
What does it involve?
Based on your plans and specification, the energy efficiency and carbon emissions figures of the proposed building are calculated.
Stage 1
Design stage. In accordance with Part L Regulations, your Inspector will require the SAP report at the same time as your Building Control Application. Without the SAP report, it is unlikely that your BCO/ AI will allow building to commence.
Stage 2
As-built stage, required when the building is completed. Without a relevant SAP calculation it is unlikely that the building will be released from Building Control.