GWYNEDD and Anglesey houses are some of the oldest and coldest in Europe a survey has found.

The county is shown to be the least energy efficient area in Wales.

An analysis of over 805,000 properties was carried out to find the areas with homes that are the most energy efficient, cheaper to run, and the worst homes for wasting energy, and most expensive.

The Everest study showed that Newport topped the list as the area with the most A/B graded - most energy efficient properties paying the least on annual bills. Some 9.7% of homes in Newport, the equivalent of 4760 homes, received an A/B grade for energy efficiency.

Areas deemed the least energy efficient areas in the ‘worst areas in Wales’ of homes receiving the worst EPC grade possible.

In the nationwide top 10, Gwynedd came in first worst, at 25.3%, Anglesey, third worst, with 19.8%, Denbighshire, was sixth worst at 14.2% and Conwy eight worst at 12.5%

Homes with an A- or B-rated EPC spend on average just £1,104 on their energy bills over three years. Most dwellings have a D rating twiths energy costs on average, of £3,228 across three years.

The average EPC rating for a dwelling in Wales is D, for those with the best rating (A or B).

A total of 77,755 dwellings nationwide received an F or G rated EPC making them the least energy efficient houses in Wales.

These residents are paying on average £5,743.50 for their energy bills across three years – 3.5 times more than those with an A or B rated EPC.