Caroline FlintGovernment reforms to make homes more energy efficient are in chaos because consumers could end up paying thousands of pounds for improvements through higher energy bills, Labour has claimed.

Under news laws, consumers will be able to pay for environmentally-friendly home improvements such as double-glazing or loft insulation, which will then be paid back through add-ons to electricity or gas bills.

To ensure millions of householders are not put off by the high cost, ministers promised a "golden rule" - the cost of repayments for the works would never be more than the money they would have otherwise spent on higher energy bills had they not made the changes.

Shadow energy and climate change minister Caroline Flint said the coalition was reneging on the promise after energy minister Greg Barker said in an answer to a written question that it was "not possible for Government to guarantee people will save money".

Ms Flint said the apparent U-turn could lead to a mis-selling scandal, with thousands of householders paying higher bills than they would have ever anticipated. She also criticised ministers for failing to stipulate interest rates on repayments for those signing up to the scheme, known as the green deal.

Speaking in the Commons, she said: "If ministers are not careful they will have a mis-selling scandal on their hands and it is one entirely of their own making. There are question marks over whether energy companies even have the technology in place to bill people correctly.

"Most importantly of all, the public, the people who are meant to be taking up the green deal, have absolutely no idea what the interest rate will be or how much it will cost them. Ministers are so desperate to prop up this policy, they are now considering whether to force it on people who find their boiler breaks down."

Ms Flint, who was speaking during a debate on the recent Queen's Speech in the Commons, also claimed the Government needed to reform its energy policy to force companies always to place pensioners on the lowest tariffs. Such a move could save four million pensioners £200 a year, she said.

Energy Secretary Ed Davey said the green deal would mean savings for low income households and pledged to release more details about how it would operate before the summer.

He said: "Later this year we will introduce the green deal bringing energy saving within reach of millions of homes across the country. A new Government-backed scheme will allow householders to get real energy efficiency improvements at no up front cost."