I thank the noble Lord for his intervention and I am glad that my remarks are invoking a certain amount of support. I totally agree with him: ground source or air source heat pumps, particularly on a large scale, are very efficient in climate change terms due to the reduction in the emission of greenhouse gases. Obviously one of the disadvantages is that you have to cost in the piping of hot water. Even with photovoltaics, the cost of those come down by something like 24% every time the number is doubled. There is a huge advantage in encouraging this because I am sure that the cost of pipes would come down, too.
Another advantage is that, as technology changes and sources of heat and efficiency go up and down, it takes only one change to get the whole community on to the most efficient fuel, burner or heat source. That is much more likely to happen than changing all the heat sources in all the houses. As I say, as our housing infrastructure catches up with the nation’s needs over the next few years—as I really hope it will, particularly in terms of affordable housing—DECC and DCLG ought to get together and ensure that these sorts of scheme are encouraged in new-build houses.