Home Energy Assessment Tool Changes – RdSAP 10 is here!

We've compiled everything you need to know about the changes made to the home energy assessment methodology in 2024. Explore how the changes will affect UK home energy efficiency ratings.

3 mins read

How is my home assessed? What is RdSAP 10?

When you have your home assessed in the UK, the company will use a set of assumptions, called RdSAP10, about your dwelling to rate your home in terms of energy efficiency. These assumptions are a standardised framework for measuring energy efficiency across the whole UK building industry and are used to generate Energy Performance Certificates (EPCs) and demonstrate compliance with UK building regulations.

Amendment version SAP10.2 is used for newly built dwellings and RdSAP10.2 is used for currently occupied buildings where they don’t have a full dataset for the building. An assessor will use the RdSAP to evaluate your home for an EPC and will use the updated framework for their assessment, report and improvement recommendations.

What’s Changed?

In Spring 2024, the Energy Company Obligation (ECO) schemes which produce this measuring framework underwent some changes for the first time in 4 years. The UK Gov Department for Energy Security & Net Zero published amendments to the Standard Assessment Procedure (SAP) and Reduced data Standard Assessment Procedure (RdSAP). These procedures are constantly being revised to increase accuracy and ensure it is fit for purpose.

The updates include the following:

Comprehensive window measurement: all windows are now measured by assessors.
Roof rooms: extra measurements are now required to accurately assess the wall thickness in roofs.
Age bands of properties: a new band has been introduced for all properties built from 2023 onwards. This considers improvements in thermal transmittance values (also known as U-values).
RdSAP assessments can now be conducted in the Isle of Man.
Added consideration of photovoltaic (PV) diverters and battery storage in properties with solar technologies.
Heat pumps will be recommended more frequently to homeowners where other improvement measures (such as adequate insulation) have already been taken.

Assessor checking the window fittings on a house - Retrofit West

What do the changes mean for my home’s energy report?

UK home energy assessments for EPCs will use the new framework which considers more factors in your home such as window size, on-site battery storage and thermal transmittance based on building age. With these changes, a more reliable picture of your home’s energy efficiency can be gained. The home improvement recommendations selected based on your assessment will encourage you to consider taking steps to improve your home’s energy efficiency.

Join the debate: Got a question? Ask our forum of trusted professionals for free today!

Ready to start your Retrofit Journey?

Save 70% on a home energy survey with a Retrofit West voucher

A home energy survey is the ideal starting point to retrofit and will guide you on energy efficiency improvements you can make in your home. This includes thermal imaging, air-tightness surveys and heat pump evaluations. Take the first step today.

*Voucher not applicable to EPC assessments.

Tell Me More