Major EPC Changes Are Now In Place.
A Major Overhaul in How Energy Performance Certificates Are Produced Came into Effect in June 2025: Here's What You Need to Know To Stay One Step Ahead.
From 15th June 2025, the Energy Performance Certificate (EPC) system underwent its most significant update in over a decade with the introduction of RdSAP 10. This new methodology aims to make EPCs more accurate, better reflect how homes are actually used, and provide clearer guidance on energy efficiency improvements.
Having a valid EPC is a legal requirement whenever a property is sold or let, and each certificate remains valid for 10 years, ensuring buyers and tenants are fully informed about the property’s energy performance
What is RdSAP 10?
The Reduced Data Standard Assessment Procedure (RdSAP) is the method used to produce EPCs for existing homes. It relies on assumptions about construction and occupancy to generate an energy efficiency rating. The new version, RdSAP 10, incorporates updated data inputs, revised assumptions, and structural changes to give a more realistic picture of a property’s energy performance.
What Are Key Changes in the EPC Assessment?
Expanded Data Collection
Assessors will now gather more detailed information, including types of glazing and their condition, heating system efficiency based on manufacturer data or model numbers, and the presence of smart heating controls. Any home improvements, such as added insulation or upgraded windows, will only be reflected if proper evidence is provided.
More Accurate Heating System Assessments
Where details of a heating system cannot be verified, previous methods relied on default assumptions, often underestimating efficiency. RdSAP 10 prioritises actual evidence. If documentation is missing, the EPC rating could be lower, even if improvements exist.
Refined Floor Area and Insulation Modelling
Updated calculation methods give a more precise view of heat retention and energy usage, helping to produce a realistic efficiency rating.
Fairer Treatment for Flats and Terraced Homes
The new system improves how heat loss is calculated for flats and mid-terrace properties, potentially giving these homes better EPC ratings than under the previous system.
What Does This Mean for Anyone Buying, Selling or Renting?
The changes mean gathering and maintaining evidence of energy improvements is more important than ever. EPCs are a legal requirement for selling and renting, and documentation for insulation, heating upgrades, and double glazing will be crucial to keep you one step ahead.
Homeowners and landlords should start collecting relevant paperwork now to avoid unnecessary retrofit costs. For tenants and buyers, the updated EPC system offers a clearer view of a home’s energy efficiency. People can make more informed choices about energy bills, while sellers can better showcase improvements, provided they can evidence them.
RdSAP 10 is a step towards more accurate, reliable EPCs that reflect real world energy use. People who prepare now by collating receipts, installation records, and manufacturer data will protect themselves from unexpected costs and ensure their properties remain compliant and attractive to both buyers and tenants.
Would you like to know how the changes might affect the value of your property? Get in touch with one of our experts today!
