Homeowners should be given special mortgages – the ‘energy mortgage’ – to allow them to make their houses more energy-efficient and less polluting, the Liberal Democrats have announced.

The ‘energy mortgage’ would be used to cover the cost of double-glazing, insulation and heating systems and would, it was claimed, make a significant impact in cutting carbon emissions and reducing energy bills.

Housing is responsible for about 27% of the UK’s CO2 emissions and the Lib Dems claim that their proposals would save 31 million tonnes of CO2 being pumped into the atmosphere each year, the equivalent to the amount produced by Britain’s cars in an 18-month period.

Lib Dem spokesperson Chris Huhne said: “Millions of people struggle to pay their fuel bills each winter, yet are unable to afford improvements on their homes to make them more energy-efficient. “With an ‘energy mortgage’, proven improvements will deliver real energy cuts that will be accessible to everyone.”

The Lib Dems’ Climate Change Starts at Home initiative was welcomed by many environmental groups, including the World Wildlife Fund. A spokesperson said: “We are impressed with the scope, ambition and credibility of the proposed scheme.

“It is good to see political parties getting to grips with the environmental challenge we face and this policy raises the bar for other parties to match.”