Phil Woolas, the environment minister, has hinted at changes in stamp duty rules for zero-carbon homes in next week’s budget.

Woolas told an audience at last week’s EcoBuild conference to “keep an eye on the budget with regard to stamp duty relief” before adding: “If I say anything more I won’t be here this time next year.”

The Treasury exempts zero-carbon homes from payment of stamp duty but uses a stricter definition of zero carbon to calculate the exemption than is adopted by the Code for Sustainable Homes.

Meanwhile, construction industry representatives are calling for reforms in the rate of VAT charged on home improvements. The Federation of Master Builders is arguing that this would help in the drive to making Britain’s existing stock greener.

The federation has gathered a coalition of organisations that are campaigning for a cut in the VAT rate charged on repairs and maintenance from f17.5% to 5%.

The Construction Products Association said it also wanted stamp duty cuts for people who improve their houses in line with the targets set by energy performance certificates.