Seven in 10 homes fall below key energy efficiency rating in Welsh county

Nation.Cymru staff

More than seven in 10 homes with an energy performance certificate in one Welsh county fall below a C rating, according to analysis of official figures.

Gwynedd has the lowest proportion of EPC-rated homes achieving Band C or above of Wales’ 22 local authority areas, with just 27.79% reaching the standard.

That means 72.21% of properties represented in the EPC data for the county are rated between Bands D and G.

Ceredigion has the second-lowest proportion achieving Band C or above, at 31.51%, followed by Powys on 34.81%.

Carmarthenshire is next at 36.56%, while Ynys Môn stands at 37.04%.

The figures come from an analysis of Office for National Statistics data covering energy performance certificate records up to the financial year ending in 2025.

An EPC rates the energy efficiency of a property from A, the most efficient, to G, the least efficient.

The figures reveal a substantial difference between parts of Wales, with Newport recording the highest proportion of EPC-rated properties achieving Band C or above, at 59.26%.

Cardiff is close behind on 58.46%, followed by the Vale of Glamorgan on 58.36% and Torfaen on 58.31%. Monmouthshire has the fifth-highest proportion at 55.12%.

At the other end of the table, Conwy and Pembrokeshire join the five lowest-ranked areas in having fewer than 40% of properties in the dataset rated C or better, at 38.41% and 38.91% respectively.

The simple average across Wales’ 22 local authority areas is 45.80%, compared with 52.69% across English local authorities.

Seventeen of Wales’ 22 council areas fall below that English benchmark.

The figures relate only to properties represented in the EPC dataset and therefore do not cover every home in Wales.

The analysis was carried out by building materials company Brick Wholesale using ONS data.

Energy bills

The findings come as households face another increase in energy costs after Ofgem confirmed its price cap will rise by 4% from October 1.

The annualised figure for a typical household paying by direct debit for gas and electricity will increase by £60, from £1,663 to £1,723, for the period from October to December.

A spokesperson for Brick Wholesale said the type and age of Wales’ housing stock were important factors when considering differences in energy efficiency.

‘Difference’

They said: “There is a difference of more than 31 percentage points between Gwynedd and Newport, showing just how much the energy performance of Welsh housing varies depending on where you live.

“This should not be interpreted as people in one area simply using more energy than people elsewhere. The age, type and construction of the homes themselves are hugely important.

“A traditional Welsh stone cottage, an older solid-brick terrace and a modern home built with insulated cavity walls are fundamentally different buildings when it comes to keeping heat inside.

“That does not mean older Welsh homes are destined to be inefficient. A sensitively upgraded solid-wall property can perform very differently from an unimproved one.

“The roof and loft, windows, doors, draughts and heating system all matter too. Two stone cottages or two brick terraces that look almost identical from outside can have very different EPC ratings depending on what has happened to them over the decades.”

The spokesperson said there could not be a “one blanket solution” for improving the efficiency of Welsh homes, particularly traditional properties with solid walls.

They added: “You cannot insulate your way out of a rise in the price of energy, but the less heat a home loses, the less energy it generally needs to maintain a comfortable temperature.”

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