Leading article: Colour of money

A television career in green property makeovers clearly beckons for Aaron and Raphaella Curtis. Unable, several years ago, to afford a home in Lewes for their seven-strong family, the Curtises built their own.

They acquired a piece of unpromising scrubland for £60,000. Using local craftsmen and materials, they constructed their five-bedroom house for £240,000. Now they are selling it for £865,000. Eat your heart out, Kirsty Allsopp.

But, in fairness, this is a special abode. Built to make the best use of a compact amount of space, it comes with extra insulation and underfloor heating powered by solar panels and a condensing gas boiler. This is a superior eco-home.

A few lessons stand out. One is that the demands from developers to be given access to green-belt land, particularly in the South-east, is often a result of a failure of imagination rather than lack of space. Another is that green construction can quite easily be a profitable exercise. The assumption is that what is good for the environment is necessarily bad for the wallet. Although the Curtises have been helped by an inflated housing market, there can be no doubt that their home's eco-conscious design has significantly boosted its value.

And then there are the public policy implications. Houses are responsible for producing about one third of the UK's carbon dioxide emissions each year. What a difference it would make to our national carbon footprint if all houses were constructed on this sensible model. The Government has announced that all new homes will have to be carbon neutral by 2016. But why wait so long? The Curtises have managed it in 2007.