Here is a report into low-cost-low-impact housing.  Unfortunately, here in Manchester, the council has demolished council housing, instead of retro-fitting the houses to improve their energy efficiency.  And then handed the land over to property developers, with the stipulation that the new homes  should meet code 5 of the national standards.  Code 6, is the new minimum standard they should be building to, though I believe they should be built to  the superior Passivhaus standards.

low-cost-low-impact-housing-2012-high-res.pdf (application/pdf Object).