The government is considering introducing a levy on domestic Energy Performance Certificates to pay for the expansion of the system used to assess the energy efficiency of houses

The news comes as the government prepares to retender the contract for the Standard Assessment Procedure (SAP) for energy rating dwellings, currently run by BRE, according to sources.

Two sources close to the matter said the Department of Energy and Climate Change (DECC) was considering whether the proposal to change SAP was feasible. Under the plan, £10 from every EPC would go towards reforming SAP and measuring the actual performance of homes rated under the system. But one source said: “SAP needs seasonal data and can be expensive so, without the levy, the cost might be beyond small businesses.”

The source said concerns remained about whether firms undertaking EPCs would pass the levy on to housebuyers.

It is thought the government spends between £500,000 and £1m a year on SAP. It is unclear how the levy would be policed.

A £10 levy on an epc would start making sap closer to the reality of buildings

Liz Reason, AECB

John Tebbit of the Construction Products Association said a robust system could cost up to £10m a year to maintain and that SAP was stretched to the limit by the move to zero-carbon homes.

Liz Reason, speaking for the Association of Environment Conscious Building (AECB), said: “A £10 levy on an EPC would generate a pot of money to start making SAP closer to the reality of what goes on in buildings.”

BRE developed SAP for Part L of the 1995 Building Regulations, but its role in rating homes with high levels of energy efficiency has become controversial.

BRE declined to comment on the retender of the SAP contract.