What steps she is taking to promote improvement of the energy efficiency of existing homes.

We have a range of programmes to support improvements in the energy efficiency of existing homes. As well as the energy performance certificates that are being introduced, we have the decent homes and Warm Front programmes, and are working with energy companies through the energy efficiency commitment. However, we recognise that we need to go further to improve the energy efficiency of existing homes.

I am sure the Minister agrees that it is most important to improve energy efficiency in existing housing stock. That would, after all, produce a win-win situation: warmer homes, lower fuel Bills, and the tackling of carbon emissions from a significant source. When will the Government extend the code for sustainable homes to existing houses, as recommended by the Sustainable Development Commission?

The code will apply to new homes. As the hon. Lady knows, we have set an ambitious time scale for all new homes to be zero-carbon within 10 years. As for her important point that we need to do more for existing homes, the energy efficiency of several million homes has already been improved, and the energy performance certificates will not only give people information about energy efficiency but suggest ways of cutting their carbon emissions and fuel Bills—improving the lagging in their lofts, perhaps, or installing cavity wall insulation. We want that information to be linked with financial support, for instance through the energy companies.

Is not one of the most important ways of encouraging householders to undertake energy efficiency measures the provision of reliable local advice? Will my right hon. Friend speak to her colleagues in other Departments about the possibility of extending the support of the Energy Saving Trust to one-stop shops and other ways of promoting such advice?

My hon. Friend is right, but it is not just a question of information. Improving energy efficiency has to be relatively easy: householders who find it a real hassle to obtain quotations or find out how to get work done are much less likely to make the necessary improvements. We are working with the Energy Saving Trust to find ways of making it easier. We also see a potential for the private sector to step in. Some companies are considering "green mortgages", which are linked to advice and suppliers. We will need to go further, however.

I, too, welcome the Minister to her extended role.

I am sure the Minister knows that the 21 million homes in this country are the economy's biggest contributors to carbon dioxide emissions, and that at least 15 million of them will still be here in 2050. Has she decided when she might begin to implement the powers she has had since 2004 to require the upgrading of those homes? That would cut Bills, improve comfort levels and tackle climate change. Can the Minister assure us that, in her new role, she will work hard with the Cabinet to persuade it to make progress on this vital aspect of climate change?

It is good to see that the hon. Gentleman is still is his place. I know that he has a long history of strong involvement in this issue, and cares about it very much.

We are considering a range of ways of helping people to improve the energy efficiency of their homes. As I have said, we have already helped several million householders with our existing programmes, and over the next few years the new energy certification programme involving energy companies is expected to help 3 or 4 million people to install cavity wall insulation. Those are substantial improvements.

I think we should concentrate first on the incentives that we can introduce and on cost-effective improvements such as cavity wall and loft insulation, but technological improvements are also needed. We need to find more cost-effective ways of improving solid-wall insulation, for instance, if we are to make a real difference in the future. We hope that the zero-carbon new homes programme will create technological spin-offs that can be applied to existing homes as well.

Do we not already have legislation that could be used to implement tougher and bolder minimum standards for energy efficiency? House builders are failing to meet the existing minimum standards on a grand scale. Why does the Minister not give the building inspectorate greater sanctioning powers and resources to enforce the new higher standards?

My hon. Friend makes an important point about enforcement. There were weaknesses in the enforcement of the 2002 building regulation improvements. Since then, we have enhanced the enforcement of the latest improvements in the building regulation standards of 2006 by putting in place a broad programme of training and other steps such as compulsory pressure testing. We need to go further, however, and we will over the next 10 years progressively set higher building regulation standards for energy efficiency in order to cut carbon emissions from homes; we are clear that improved enforcement must be a part of that programme.