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It’s been announced that rdSAP10 should be ready for release on June 15th 2025, following years of delays. 

This new calculation tool will replace to current rdSAP tool and be used to measure the energy performance of existing dwellings, and to generate their Energy Performance Certificates. 

Domestic Energy Assessors currently use a version of SAP that is over a decade old. This long-awaited, highly anticipated upgrade is being welcomed across the industry. 

Why Does It Matter? 

As it stands today, if a surveyor visits your house and creates an EPC, the calculations behind the reports are outdated and no longer reflect the UK’s current trajectory towards net zero. 

For example, rdSAP currently considers mains gas to be greener than electricity – something that was true until about seven years ago. However, as the UK shifts towards home-made, clean power, fossil fuel heating systems are being left behind.  

The results that are generated by rdSAP10 will be re-prioritised, so more homes will receive recommendations for low-carbon, high efficiency heat pumps as a viable replacement for aging boilers. 

Also, surveyors will have an improved list of technologies to pick from, improving the accuracy of the results. For example, under the current system, a home with solar panels connected to a battery cannot have this feature recorded – something that rdSAP10 will address.  

Similarly, newer homes that underwent air tests at the time of construction will now be able to include these results, confirming better fabric performance and improving EPC accuracy – another feature missing from the current system.  

The accuracy of surveying is also being improved, most notably by requiring detailed information about the property’s windows, rather than allowing for a rough estimate of glazing sizes. Homes with rooms-in-roof will also be measured with greater accuracy. While these changes may slightly increase the survey duration, they will significantly improve result quality.  

What Does This Mean for Homeowners? 

For the homeowner, there’s practically no change. The survey will take place in the usual way, and Energy Performance Certificates and Recommendation Reports will be produced that look exactly like the current ones. 

However, the calculations used to generate the EPC ratings will be more accurate, forward-thinking and better aligned with our net-zero plans. 

It should be noted, the release of rdSAP10 is entirely separate to the recent consultations about EPC reform and the launch of the Home Energy Model. These changes are at least a couple of years down the road. Look out for future articles about the new-look EPCs and what that means for homeowners, buyers and renovation projects.