You have to get the big housebuilders on side first, which is very difficult, they are reluctant to change. I have worked with the likes of Bellway, Bovis, Barratt etc for over 12 years and they challenge even small changes to the industry that might put costs up, especially in the current climate. Currently, the biggest problem for the industry is getting bricks, blocks and roof tiles as the manufacturers shut down production and it's not easy to get back up to speed, so applying massive changes of this type would be fought against. Where you do see PV panels etc is in the social housing sector, where they get the tariff back themselves.