British Gas has been criticised for lobbying to reduce plans for insulating some of the UK’s coldest homes.
The firm persuaded ministers to lower their ambition by two-thirds after it failed to meet existing mandatory targets for solid-wall insulation.
Rival firms say British Gas’s lobbying has put up to 10,000 jobs at risk and may jeopardise the fledgling solid-wall insulation industry.
But BG said there were cheaper ways to save on bills and cut carbon emissions.
The government’s energy efficiency programme previously set a target for insulating 300,000 cold homes without cavity walls by March 2017.
The work is expensive and labour-intensive, but it cuts £400 to £500 from a home energy bill and is a guaranteed way of permanently reducing costs for consumers.
The insulation was due to be carried out by energy firms under the ECO scheme, which imposes a levy of around £50 on the average household bill.
Some firms created large teams of home insulators and were on schedule to complete the work on time. But British Gas insulated only one in six of the solid-walled homes it was supposed to.
It also said the costs of carrying out the energy-saving scheme were much higher than estimates from its rivals.