Social rented dwellings have the highest median energy efficiency score out of all property types in England and Wales, new data from the Office for National Statistics (ONS) shows.

Overall, in England, the average energy efficiency score for a social rented detached property is 64, for a semi-detached, 67, for a terraced house 68, and for a flat and maisonette, 72.

In Wales these read as 67, 67, 68, and 73, respectively.

The poorest performing property type, the private rental sector (PRS) stock, scores as 58, 60, 62, and 68 in England and as 56, 61, 61, and 68 in Wales (here, the PRS proves to be marginally better than the owner-occupied sector in the semi-detached and terraced categories).

The owner-occupier sector, while overall scoring higher than the PRS, fairs little better at any property type.

The ONS data adds that, for all dwellings, the median energy efficiency score in England up to March 2021 is 66 and, in Wales, 64 (band D equivalent for both).

And in both countries, the most energy efficient property type, with a median score of 72, which is band C, is the flat and maisonette category.

The government intends to have as many properties as possible score at least 69 – band C- by 2035. However, the age variation of housing stock could prove a challenge.

The data shows that properties built after 2012 score a median average of 83 (band B) while those built before 1900 score, on average 54 in England and 51 in Wales – band E.

And 23% of houses in Wales, the ONS points out, are ‘older’ (ranging from prior 1900 to 1929 in origin) against 16% in England.

“People in older properties have a mountain to climb if they’re going to hit the government’s energy efficient targets,” says Hargreaves Lansdown personal finance analyst Sarah Coles.

“A typical Victorian property is faced with insulating its way from an average band E to an average band C. This could prove too expensive, leaving the owners of these properties out in the cold.

“The government is considering encouraging people to take action by manipulating the mortgage market. Mortgage lenders could be forced to target lending on more efficient homes, and encouraged to provide additional funds so people can make improvements.”

She continues: “[It] won’t force anyone to make changes where they are unaffordable. However, if you’re living in a Victorian semi with a rating of band E, you may well struggle to find a mortgage lender offering a competitive deal. When you come to sell, this could mean buyers are thinner on the ground, which is likely to depress the price.”

Propertymark policy manager Timothy Douglas says: “It is now well over twelve months since all properties rented on a relevant tenancy in the private rented sector in England and Wales must meet the EPC band E rating, so it is good to see letting agents and landlords meeting the requirements and adhering to the rules – everyone wants to see rented property that is safe, secure and warm.

“However, the government’s latest proposals for EPC band C presents a much tougher challenge for many properties across the country.

“It is of no surprise that social rented dwellings are more energy efficient because the social rented sector has received significantly more funding to improve energy efficiency than the private rented sector, despite being the smallest housing tenure in England.

“With the wide range of property types in the private rented sector and proposals for a £10,000 cost cap, landlords across the country are being presented with financial and practical challenges, which if not tackled, could result in a reduction in supply and landlords exiting the market.”