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 and news
A now architectural practice looks back at its concept project for a sustainable oceanic settlement 25 years on.
Copyright and Artificial Intelligence
Government report and back track on copyright opt out for AI training but no clear preferred alternative as yet.
Embedding AI tools into architectural education
Beyond the render: LMU share how student led research is shaping the future of visualisation workflows.
Why document control still fails UK construction projects
A Chartered Quantity Surveyor explains what needs to change and how.
Inspiration for a new 2026 wave of Irish construction professionals.
New planning reforms and Warm Homes Bill
Take centre stage at UK Construction Week London.
A brief run down of changes intentions from April in an onwards.
Reslating an ancient water mill
A rare opportunity to record, study and repair early vernacular roofs.
CIOB Apprentice of the Year 2025/26
Construction apprentice from Lincoln Mia Owen wins this years title.
Insulation solutions with less waste for a circular economy
Rob Firman, Technical and Specification Manager, Polyfoam XPS explains.
Recycled waste plastic in construction
Hierarchy, prevention to disposal, plastic types and approaches.
UK Net Zero Carbon Buildings Standard V1 published
Free-to-access technical standard to enable robust proof of a decarbonising built environment.
Prostate Cancer Awareness Month
Why talking about prostate cancer matters in construction.
The Architectural Technology podcast: Where it's AT
Catch up for free, subscribe and share with your network.
The Association of Consultant Architects recap
A reintroduction and recap of ACA President; Patrick Inglis' Autumn update.
The Home Energy Model and its wrappers
From SAP to HEM, EPC for MEES and FHS assessment wrappers.
Future Homes Standard Essentials launched
Future Homes Hub launches new campaign to help sector prepare for the implementation of new building standards.
Building Safety recap February, 2026
Our regular run-down of key building safety related events of the month.
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.