Contractors have warned Ed Davey that he has inherited a tough ministerial brief after becoming energy and climate change secretary following the resignation of Chris Huhne.
Mr Davey will have the smallest ministerial budget, but will be expected to lead on affordable energy while driving through ambitious carbon reduction targets - largely through changes to the built environment.
The October deadline for the introduction of the Green Deal is likely to put this policy at the top of his in-tray.
David Strong, a consultant who advises the government on sustainable built environment, said Mr Davey must iron out details on Green Deal warranties, ease the transition for companies from Carbon Emissions Reduction Target to Energy Company Obligation, and build some compelling incentives into the scheme for consumers.
Prof Strong said: “The solution must be to introduce some more carrots and sticks.” He said the “stick” was being provided - albeit with loopholes - through the draft revisions to Part L of the building regulations.
However, Mr Davey had to make sure that there were better incentives.
Construction Products Association external affairs director Simon Storer said there was nobody in the industry who believed the government’s as yet unattributed £200 million of incentives would be anywhere near enough to ensure success.
In June 2010 Mr Huhne said up to 14m homes could be retrofitted through the Green Deal by 2020 - creating as many as 250,000 additional maintenance jobs.
UK Green Building Council policy director John Alker said a more sober estimate of even partial success would require uptake of around 500,000 homes a year, rising to 1m homes a year by the end of the decade.
Mr Alker added that Mr Davey would need to ensure this consistent uptake was not disrupted by a late change of heart from the Treasury over potential incentives.
One of Mr Huhne’s final ministerial challenges before he resigned over his charge for perverting the course of justice was the scaling back of entitlements to Feed-in Tariffs for solar power.
Mr Davey is replacing a well-known heavyweight frontbencher.
Before being handed the DECC brief in the government, Mr Huhne had shadowed the Home Office brief and tussled with Nick Clegg for leadership of the Liberal Democrats. Mr Storer said: “[Mr Davey] has to come in a step up to secretary of state. He has a lot to do.
“The Green Deal is a big policy for the government. He has big shoes to fill. He has less experience, fewer of the political bruises and strengths that perhaps Chris Huhne had.”
However, Liz Male, chairman of the tradesman standards organisation TrustMark, said Mr Davey’s time as a minister in BIS meant he would have a more rounded attitude to government that his predecessor.