EPC Rating Distribution

It's possible to produce a graph of EPC rating distribution across all dwellings by downloading information from the OpenDataCommunities websitea at the following URL:

https://epc.opendatacommunities.org/login

The graph above shows the distribution of EPC ratings between 1 and 100 of all properties in Wiltshire as at the end of January 2025. This includes only valid EPCs, ie ones that are still within their 10 year expiry window.

On the very left, with an EPC rating of G1 are a small but notable number of properties with the worst possible EPC rating. There were 107 properties with this rating. These tend to be older properties with poor building fabric combined with poor heating systems.

In contrast, the highest EPC rating was A167 (off the graph here), which was a farm house connected to a massive solar array on a nearby barn.

The spike in EPC ratings around the 84A level is due to new builds, and illustrates the effect of modern building regulations. This is demonstrated below by the separate graphs for existing dwelling and new buildings.

This demonstrates the strength of modern building regulations on EPC ratings of new properties: