The most significant change to domestic EPCs in over a decade is almost here. From 15th June 2025, RdSAP 10 will officially replace RdSAP 9.94 as the method for assessing the energy performance of existing homes.
At Essex EPC Service, we’re fully prepared for the switch—and here’s what you need to know as a homeowner, landlord, or retrofit professional in Essex and beyond.
What Is RdSAP 10?
RdSAP (Reduced Data Standard Assessment Procedure) is used for calculating EPC ratings for existing dwellings. Version 10 is a long-awaited update that brings the methodology in line with full SAP 10.2, enhancing accuracy and detail.
New features include:
Expanded wall construction types (e.g. park homes, timber frame with insulation)
More precise inputs for heating systems and controls
Updated assumptions for ventilation, lighting, and renewables
Greater support for modern technologies like air source heat pumps and solar panels
But with that precision comes a trade-off…
More Detail = Longer Assessments
To produce a compliant RdSAP 10 EPC, assessors must now gather significantly more on-site data. This includes:
Additional photographs and measured drawings
Specific details on heating controls, ventilation, and insulation
Confirmation of party wall construction and roof types
More evidence to support data inputs
As a result, EPC assessments will take longer than before—sometimes up to an extra hour, depending on the size and complexity of the property.
Why EPC Costs Will Increase
Because of the increased time, admin, and verification required, EPC prices are expected to rise across the industry from 15th June onwards.
At Essex EPC Service, we aim to keep our pricing competitive, but the update reflects:
More time on site
More post-visit evidence checks
Higher technical standards to meet compliance
What You Should Do Now
If you’re planning to:
Sell or let a property this summer
Apply for grants under ECO4, GBIS, or local authority schemes
Book a retrofit assessment for improvement works
Then now is the time to act. Avoid delays and price increases by booking your EPC ahead of the 15th June deadline.
You can book directly with us via our online contact form or call us for advice.
Helping You Stay Compliant
At Essex EPC Service, our accredited Domestic Energy Assessors and Retrofit Assessors are fully trained in the new RdSAP 10 standards. We offer:
Standard EPC assessments
Retrofit assessments
Property modelling and improvement plans
Honest advice to help you reduce energy bills and emissions
Ready to Book?
Don’t get caught out by the changes. Book with confidence today.
Book your RdSAP 10 EPC with Essex EPC Service
Or call us directly at 07862 058174