What a great way to drive buyers to the burbs in search of energy "efficient" new houses - and the additional but unlabelled environmental costs of what it took to bulldoze the farmer's fields, build the roads and utilities, build that subdivision of drywall boxes, the costs of the resultant commute, and the quality of life misery of both the commute and a neighbourhood that isn't within walking distance of anything.  Instead, try reintroducing the renovation subsidy to help fix up the quality housing already built, and remove the wealthy car-buyer's hybrid car subsidy for a start - this change would benefit owners at all income levels, home buyers, green industry, renovation labour...  The environmental costs of life are much more complicated than some oversimplified label can capture;  this kind of nonsense will only encourage the unscrupulous to exploit the ignorant.