Wales has highest share of lower-rated EPC records - but also leads on recorded solar PV
New analysis reveals a more complicated Welsh energy picture, with lower-rated housing existing alongside comparatively strong renewable-technology evidence.
Wales has the highest proportion of EPC D-or-below records of any of the ten regions in the EPC Atlas analysis, at 54.09%. It also has the highest regional Solar PV: Yes share at 2.106%.
Among qualifying local authorities, Ceredigion has the strongest explicit off-gas result in the full England-and-Wales analysis: 69.64% among records where mains-gas status is known.
Heat-pump evidence appears on 9.51% of Ceredigion records, while Powys records 54.50% explicit off-gas among known-status records.
The findings show why the Welsh picture should not be reduced to a single “best” or “worst” label: older and lower-rated EPC evidence, rural/off-gas geography and renewable-technology evidence coexist.
Key figures
- 902,603 searchable Wales records.
- 271,024 are D-or-below + potential A/B.
- 160,361 are additionally owner-occupied classification and Houses.
- 41.19% show Poor/Very Poor wall-efficiency evidence.
About the research
The EPC Atlas UK Data Book 2026 Volume One v0.3 analyses 17,624,989 searchable records across ten England-and-Wales regional datasets. Scotland and Northern Ireland are outside the research corpus.
About EPC Atlas
EPC Atlas is a UK property and energy-performance data research and intelligence project designed to make large-scale EPC evidence searchable, comparable and easier to analyse at national, regional and local level.