Guidance

Standard Assessment Procedure

Overview of how a home's energy performance is calculated using the Standard Assessment Procedure (SAP).

From:
Department for Energy Security and Net Zero
Published
22 January 2013
Last updated
148 MayJune 20252026 — See all updates

Update: 148 MayJune 20252026

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Overview

The Standard Assessment Procedure (SAP) for the energy rating of dwellings is the methodology currently used by the government to estimate the energy performance of homes. The methodology has 2 main uses:

Non-domestic buildings use a different methodology, called the Simplified Building Energy Model (SBEM)(SBEM).

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 was developed by the Building Research Establishment (BRE) for the former Department of the Environment and was based on the BRE Domestic Energy Model (BREDEM). SAP was first published in 1993 and has since been updated periodically, in 1998, 2001, 2005, 2009, 2012, 2022 and most recently in 2022.2026.

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 of SAP is  is SAP 10.2 10.3.

The current version of of RdSAP is  is RdSAP 2012 10.0.1.

The government is currently working on an RdSAP update (RdSAP 10), which we aim to be available for use by 15 June 2025.

You can find detail of the upcoming changes in thethe SAP and RdSAP 10 specificationspecifications.

You can find more information on on SAP and  and RdSAP on on the Building Research Establishment’s (BRE) site. site.

The future of SAP

Following recommendations by the Climate Change Committee (CCC), and a scoping study 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 for net zero.

The Home Energy Model

InThe DecemberHome 2023,Energy weModel publishedwill areplace consultationthe SAP for onthe thisenergy newrating methodologyof –dwellings.

Consultations:

TheTechnical documents:

Scoping study:

Updates to this page

Published 22 January 2013
Last updated 148 MayJune 20252026 + show all updates

  2. A version of SAP will be made available alongside the new Home Energy Model software when the Future Homes Standard regulations are laid before Parliament.

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