Standard Assessment Procedure
Overview of how a home's energy performance is calculated using the Standard Assessment Procedure (SAP).
Overview
The is the methodology currently used by the government to estimate the energy performance of homes. The methodology has 2 main uses:
- to demonstrate compliance of new homes with Part L of the Building Regulations
- to generate Energy Performance Certificates (EPCs) for all homes, which advise occupants, prospective buyers, landlords, and renters of the energy performance of a property
Non-domestic buildings use a different methodology, called the .
SAP plays a key role in developing, implementing, and monitoring government policies on energy efficiency, fuel poverty and heat decarbonisation, and is used across the whole building industry.
The history of SAP
SAP聽was developed by the聽Building Research Establishment (BRE)聽for the former Department of the Environment and was based on the聽. SAP was first published in 1993 and has since been updated periodically, in 1998, 2001, 2005, 2009, 2012, and most recently in 2022.
In 1994, SAP was first cited in the Building Regulations as the means of assessing the energy performance of dwellings. In 2007 it was adopted as the methodology behind Energy Performance Certificates (EPCs).
Reduced data SAP (RdSAP) was introduced in 2005 as a simpler and lower cost method for assessing existing dwellings. An RdSAP assessment will use a set of assumptions about the dwelling, reducing the volume of data an energy assessor must collect.
Current methodologies
The current version of SAP is .
The current version of RdSAP is .
The government is currently working on an聽RdSAP聽update (RdSAP聽10), which will be available for use in early 2025.
You can find detail of the upcoming changes in the .
You can find more information on site.
The future of SAP
Following and a commissioned by the former Department for Business, Energy and Industrial Strategy, the government is developing a new methodology to increase its accuracy, robustness, and ensure it is fit net zero.
In December 2023, we published a consultation on this new methodology 鈥� the Home Energy Model (closed on 27 March 2024) 鈥� so that industry can participate in the ongoing development process.
The Home Energy Model is still under development and its first version will be implemented alongside the Future Homes Standard in 2025.
Updates to this page
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Added link to a consultation on the Home Energy Model, a new methodology which will replace SAP.
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Updated information about Standard Assessment Procedure SAP10.2, and the timeline for the Reduced data SAP (RdSAP) update.
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Updated with information about SAP 10.2 which comes into force in summer 2022, and SAP 11, planned for 2025.
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Minor updates to the guide on SAP adding in new links to BRE.
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First published.