Totnes eco-home 'slashes heating bills'
7 November 2013 Last updated at 11:09 GMT
A man who spent £300,000 converting his house has said it was worth the money to reduce bills.
Adam Dadeby, from Totnes in Devon, says he now pays £16 a month for gas in his three-bedroom home.
The house was built in 1971 and converted two years ago.
The walls, floors and roof are packed with extra insulation and pipes send warm air around the house.