Not all that green after all.
Ministers have set a target for all new housing to meet the highest "level six" sustainability rating by 2016 – which would in effect see them rated as "carbon neutral".
To meet the standard, all the energy used to heat, light and run appliances within the home would all have to come from renewable sources. The houses themselves would also have to be built to reduce energy usage by 100 per cent more than current building regulation standards.
But homes in eco-towns, the first of which will come into existence at around the same time, will only have to be built to the lower "level three" rating -meaning they have to improve on current energy use standards by 25 per cent.