Reduced Data Standard Assessment Procedure
Energy Performance of Buildings Certificates: glossary, originally published by the Ministry of Housing, Communities & Local Government in 2014, defines the Reduced Data Standard Assessment Procedure (RdSAP) as: ‘…the government approved methodology for producing an EPC (Energy Performance Certificate) for existing dwellings. For existing dwellings much of the information required to assess the energy performance is not readily available so an on-site survey is needed to collect it. To minimise inconvenience for the homeowner, the method to assess energy performance was adapted to include a set of assumptions about the dwelling based on conventions and requirements at the time the dwelling was constructed. This means that less information is required from the homeowner for the assessment than for a newly constructed dwelling.’
On 15 June 2025, this software tool and calculation methodology which is used to create EPCs for existing buildings, the (rdSAP) will be updated from RdSAP v9.94 to RdSAP v10.0. It is the most significant change in the procedure in some 10 years, with a vastly increased number of data points that go towards the final rating and the inclusion of ventilation, as well as electricla heating systems such as heat pumps.
[edit] Related articles on Designing Buildings
- Approved document L.
- Display energy certificate.
- Emission rates.
- Energy certificates for buildings.
- Energy Efficiency Rating.
- Energy performance certificate EPC
- Energy Performance of Buildings Directive.
- Environmental impact rating.
- Minimum energy efficiency standard (MEES).
- National Calculation Method.
Featured articles
Check out some of the best features and news from Designing Buildings as well as key stories from around the web.
National Planning Policy Framework
Understanding the 2026 changes.
ECA's public affairs priorities
Member consultation opens to shape priorities for 2027 to 2030.
Dutyholder responsibilities from 1 July 2026.
Where performance meets practice
The Building Envelope Stage at UKCW Birmingham.
CIAT publishes briefing on planning reforms.
Leaders in Learning for Practice Network
Call for conservation leaders in learning to register interest in new network.
The importance of early engagement
Construction lessons from the Trillium HealthWorks Experience Centre.
Mayors are to be given planning call in powers
Mayors across England will be able to make the most important planning decisions.
The Master Builder: William Butterfield and his times. Book review.
Why construction can't afford to ignore the skills gap.
Building Safety Regulator, 19 August
Gill Kernick appointed Independent Chair of Residents’ Panel.
Connecting knowledge, technology and conservation
Building competence for the future of built heritage.


















Comments
[edit] To make a comment about this article, click 'Add a comment' above. Separate your comments from any existing comments by inserting a horizontal line.