Or, at least that was the case until last week, when it published its carbon transition plan: practical proposals to make just about everything more energy-efficient. The aim is to reduce carbon emission in 2020 to 34% of their level in 1990.

The plan should be broadly welcomed, largely because it contains achievable targets backed up by more detail than usual, and there is plenty in there to help the construction industry. For example it proposes that 15% of the target should be met by improving existing homes including whole-house energy-efficiency makeovers for seven million of them by 2020.

There are also proposals for “pay as you save” mortgages where loans for energy-efficiency improvements are funded by saving on bills. And there are proposals to pay sensible tariffs to householders who contribute electricity to the National Grid from their photovoltaic tiles and wind turbines, which should boost the renewable energy industry.

Meanwhile, we had another piece of good news with the announcement that a definition of zero carbon has finally been agreed, and that it dovetails neatly with the carbon transition plan. Ever since the Code for Sustainable Homes was published the industry has been complaining about the difficulty and expense of making homes self-sufficient in energy.

So there was plenty to celebrate when John Healey, the housing minister, announced that only 70% of a new home’s energy needs had to be met onsite. The news has been welcomed by the industry as tough, realistic and (above all) doable, helped no doubt by the estimate that it will make a new home £7,000 cheaper than it would have been under the old proposals.

The remaining 30% of energy for new housing will come from “allowable solutions”. Housebuilders will be required to invest in low carbon heat infrastructure or export spare heat to other developments, invest in energy-efficient appliances or possibly fund offsite wind farms. On the policy level, this fits well with the carbon transition plan, but like all grand strategies the devil is in the detail. What sorts of allowable solution should get priority – windfarms or district heating?

The solutions must be good for 30 years after the home has been built so will the fridge police be able to inspect our kitchens to check that we’ve replace like with like? And speaking of the police, who is going to administer and enforce this, building control or a new sort of enforcer? And who is going to pay for it? People would also like to know how much of that 70% will come from energy-efficient construction and how much can be met by onsite energy generation and biomass. The government has put off answering these posers until the end of this year, which leaves even less time for the industry to help the government hit its targets.

While we are on the subject of devils and details, consider the problem of how to make historic buildings use less energy. The consultation on Part L proposes removing the statutory exemption for historic buildings in favour of a fairly woolly statement that “special consideration” should be given to a building’s historic character. English Heritage isn’t against the idea, but understandably it is worried that jobworths may interpret that to mean double glazing should be added to stained glass windows.

Obviously, the way to address this problem is to make sure building control officers appreciate the meaning of special considerations. This means more money and training has to be provided to make sure we get informed, intelligent enforcement. It looks like a theme is beginning to emerge here …