Portsmouth ranks low in UK energy efficiency survey

At the same time, the push to reach net-zero targets is putting more pressure on cities to improve. Some places have made progress with new housing and upgrades, but many are still dealing with older homes that lose heat and cost residents more money.

A new study by Wolf River Electric looked at official EPC data for cities across the UK to identify where homes are least and most energy efficient, using efficiency scores to compare performance nationwide.

Portsmouth ranks joint 12th nationally with a median energy efficiency score of 66, alongside Brighton and Hove, Gloucester, Lancaster, Leeds, and Manchester. Much of the city’s housing stock consists of older terraces, Victorian and Edwardian homes, and mid-20th-century suburban housing. Many of these properties lack modern insulation and efficient heating systems, meaning residents often face higher energy bills and colder homes, especially during the winter months.

Colchester tops the list with a score of 60, followed by Armagh and Chichester at 63. Peterborough and Sunderland share fourth place on 64. These results show the challenge older housing presents for energy efficiency across the UK.

At the opposite end of the ranking, Stirling and Chelmsford share the top spot with scores of 83. Winchester, Bath, Salford, and Glasgow also perform strongly, benefiting from newer housing, modernised stock, and regeneration projects that improve energy performance.

Justin Nielsen, energy expert at Wolf River Electric, said:

"Energy efficiency in the home is no longer just about being environmentally conscious, it’s directly linked to household finances. In the UK, where winters are long and damp, poorly insulated homes can lose a significant amount of heat through walls, roofs and windows. That lost heat translates straight into higher energy bills."

"The difference between an older, poorly rated property and a modern, energy-efficient home can easily run into hundreds of pounds per year. In some cases, households upgrading from an EPC band E or F to band C could see annual savings of £300 to £500, depending on property size and energy usage. Over time, those savings really add up."

"Improvements don’t always require a full renovation. Better loft insulation, cavity wall insulation, upgrading to a modern condensing boiler, installing double or triple glazing, or even smart thermostats can all make measurable differences. For homeowners, these upgrades not only cut bills but also improve comfort, with fewer cold spots, fewer draughts, and a more stable indoor temperature."

"As the UK moves towards stricter energy standards and net-zero goals, properties with poor EPC ratings may become less attractive on the market. Energy efficiency isn’t just a utility issue. It’s becoming a property value issue too."

List of UK areas with the least energy-efficient homes: