King Charles and Prince William Face £10 Million Bill Under New Rental Energy Rules
King Charles and Prince William face an estimated £10 million bill to bring their rental properties up to new energy efficiency standards by 2030, according to a Guardian investigation published on 17 August 2026.
The government has announced that all private rental properties in England must hold an Energy Performance Certificate (EPC) rating of at least C by 2030, raising the previous legal minimum of E. The EPC system, introduced in England and Wales in 2007, grades properties on a scale from A, the most efficient, to G. The change means landlords across the country face the same obligation, regardless of who owns the land.
The Guardian surveyed rental properties across the Sandringham Estate, which King Charles owns privately, and the Duchies of Lancaster and Cornwall, the landed estates that provide income to the sovereign and the heir to the throne respectively. Almost 90 per cent of the properties examined did not meet the required C rating The Guardian.
The picture varies by estate. At Sandringham, 99 per cent of EPCs examined were rated between D and G. More than 90 per cent of Duchy of Lancaster properties sat at D or below. The Duchy of Cornwall fared somewhat better, though 80 per cent of its rental properties still fell between D and G. Some newer Duchy of Cornwall developments, including projects in Dorset and Cornwall, do already meet the C standard.
The estimated cost to bring each substandard property up to C is around £10,000, bringing the total across the three estates to roughly £10 million. Landlords who fail to meet the 2030 deadline face fines of up to £30,000 per property.
A Duchy of Cornwall spokesperson acknowledged that upgrading homes would be "a challenge" owing to its "unique portfolio," which includes many historic buildings in isolated rural and island locations where retrofit work is more complex and costly The Guardian.
The three estates operate under different ownership structures. The Sandringham Estate is King Charles's private property, bought by the royal family in 1862. The Duchy of Lancaster belongs to the sovereign as an institution; Charles receives its profits but does not own the land privately. The Duchy of Cornwall, established in 1337, passed to Prince William upon Charles's accession to the throne and provides private income to William and his family.
The existing Minimum Energy Efficiency Standards have required rental properties to reach at least EPC band E since 2018. The government's consultation on the new C standard, published in February 2025, applies to the entire private rented sector, from a tenant in a one-bedroom flat to the Crown itself.
