What are the EPC rules and why are so many of Prince William’s tenants not protected by them?

Since 2020 it has been illegal for a landlord to rent out a home with an energy efficiency rating below an E.

But there are exemptions and gaps in the rules which the Duchy appears to exploit so that large chunks of Prince William’s £1.3bn property empire do not have to comply with modern standards. It leaves scores of his tenants, many of them elderly or on low incomes, stuck for years in properties the Government considers “sub-standard”.

Energy Performance Certificates or EPCs have been legally required every time a domestic property is put up for sale or rent since 2008. They use a colour-coded bar chart, similar to the ones on appliances like fridges, to rate a property from a green “A” to a red “G” – with “A” the most efficient and cheapest to run and G the coldest and most expensive to heat.

In 2018, the Minimum Energy Efficiency Standards or MEES regulations came into force for all new tenancies, and two years later they were extended to all tenancies, including those that had already started. Leading industry expert Andrew Parkin, director of Elmhurst Energy and chair of the trade body Property Energy Professionals Association, told us: “Under Minimum Energy Efficiency Standards regulations, any property that doesn’t achieve an E or better is in breach of those regulations unless they have a valid exemption. And there are a number of exemptions that can apply as long as evidence has been provided.”

There are six exemptions landlords can register for, and they include if the work costs more than £3,500, if all the possible improvements have been made and if the tenant refuses to agree to the work. Our research with Channel 4 Dispatches and Vera Productions shows the Duchy has applied just 10 times for exemptions and the most common reason, used four times, was that the work would cost more than £3,500 to complete.

Three times it argued that installing wall insulation would “negatively impact” its building, twice that “consent” to the work was refused and one it claimed exemption as all improvements had been made and yet the property had still not reached an E. We found 70 Duchy properties rated F and G with no exemption.