The Government should concentrate on the UK's 26 million existing homes instead of its plans for controversial eco-towns, Grand Designs host Kevin McCloud said today.
The 51-year-old television presenter said it was "a lot less energy and it's a lot less effort to work on the existing housing stock rather than tear it all down and build again".
He was speaking ahead of a Government announcement on Thursday which is expected to significantly scale down its plans for eco-towns.
Mr McCloud said: "Eco-towns are nothing if people commute to work, and you've got to make them a place where people live and stay and base their lives.
"We need to concentrate on the 26 million existing homes that we've got in this country that are responsible for about 27% of carbon emissions."
He urged the Government to kick-start a green refurbishment programme for UK homes by tackling poorly insulated, inefficient housing stock, creating the potential to reduce homeowners' energy bills.
The Committee on Climate Change estimated that by retrofitting existing housing stock, nine million tonnes of carbon dioxide could be saved - the equivalent to the average CO2 output of more than 1.5 million homes per year.
The market for green refurbishment and improvement could be worth between £3.5 billion and £6.5 billion per year and thousands of new jobs could be created, the Federation of Master Builders said.
Research by the Energy Saving Trust also found Britons could save on average £300 a year on household bills by being more energy efficient and improving heating and insulation in the home.
The expected climb-down on the controversial eco-towns follows criticism from Tories, environmental groups and residents in the areas affected amid concerns over impacts on the planning system, transport links, jobs provision, the environmental impacts of the sites and whether they can actually deliver the green, affordable housing that is promised.
The environmentally-friendly new towns were the first major policy announced by Gordon Brown as he launched his bid to take over as Prime Minister in 2007 and the idea was expanded from five towns to 10 in September 2007 following an initial positive response.
But even before the initial shortlist of 15 possible towns was unveiled in April, communities were marching against sites they believed had been earmarked by developers or councils for the new eco-town settlements.
Many protesters were concerned that several of the plans thought to have been submitted were on sites where conventional developments had failed to get off the ground.
High profile opponents of various schemes around the country have included actress Judi Dench, author Jilly Cooper and tennis star Tim Henman's father Tony Henman.
The eco-towns, intended to tackle the twin problems of housing shortages and climate change, have to be carbon zero as a whole, be an "exemplar" in one area of environmental development and have at least 30% affordable housing.
Up to 10 are proposed, with five being built by 2016 and a further five by 2020.
It is expected the Government will announce just three or four of the new towns on Thursday.