The cost of a cold home: what Britain's least efficient homes cost to heat, by band, age and area

The age effect

The single clearest predictor of running cost is when the home was built. The older the stock, the higher the bill, and the relationship is almost perfectly ordered.

A home built before 1900 costs a modelled £1,252 a year to heat, and 85% of these homes fall below band C. A home built in 2020 costs £294. The pre-1900 home costs more than four times as much to keep warm. Solid walls, single glazing where it survives, high ceilings and leaky fabric all add up. This is the structural reason the green premium and the cost of heating both track so closely to the age of the housing stock.

The geography of a cold home

Running cost also varies by region, and the pattern is the inverse of the price map. The cheapest places to buy are often the most expensive to heat. Wales and Yorkshire top the regional table, while London is cheapest, held down by its smaller homes and large flat stock.

The most expensive places to heat are rural, often off the gas grid, and full of older and larger homes. Westmorland and Lonsdale, Dwyfor Meirionnydd and Hexham combine all three factors. A larger stone-built home heated by oil in the Lakes or rural Wales is close to the worst case for running cost. We mapped the off-grid heating pattern in detail in our home heating study.

What this means

For buyers, the heating cost is the bill behind the band. A cheap older home can carry a heating cost that erases the saving on the purchase price within a few years. Read the modelled cost on the certificate, not just the letter.

For sellers, an efficient home now has a number worth quoting. The running-cost gap is a concrete figure that lands with buyers facing high energy prices.

Before buying any home, it is worth pulling its EPC rating, heating cost and the rest of its record. We also looked at how efficiency feeds through to sale price in our green premium study.

Methodology and caveats

Source data: the Energy Performance Certificate register for England and Wales, 23.4 million domestic certificates lodged between 2012 and mid-2026. The heating cost is the certificate's own modelled current annual figure.

The cost is modelled, not metered. It assumes a standard occupancy and heating pattern, so it is a like-for-like comparison rather than a prediction of any single household's bill. The unit prices baked into a certificate reflect the assumptions at its assessment date, so older certificates carry older price assumptions. Treat the figures as a consistent way to rank homes, not as a current energy bill.

Coverage: a certificate exists only for homes sold, let or built since 2008, roughly 60% of the stock. Long-held older homes are under-represented, which if anything understates the true cost of heating the worst stock. All figures are medians except the regional and constituency averages, which use the mean modelled cost.