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.
Communities will be able to build their own clean energy.
Why diversity and inclusion matters for SMEs
CIOB’s D&I Charter shows how practical changes can support long-term growth.
Cut electricity bills to power growth
Coalition sends joint letter to the Chancellor.
Gasholders: a history in pictures. Book review.
Recognition, influence and growth
SocEnv identifies three strategic pillars in new strategy to 2045.
Discover the future of roofing, cladding and insulation.
New guidance for professional practice, cultural change and regulation in social housing.
The heritage of nuclear and conventional power stations.
New measures to stop people being ripped off
Government to protect families from cowboy builders and aggressive bailiffs.
New Futurebuild showcase brings an innovation-first approach.
National Planning Policy Framework
Understanding the 2026 changes.
ECA's public affairs priorities
Member consultation opens to shape priorities for 2027 to 2030.


















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.