I’ve asked before whether McMansions can ever be green. Australia is proposing energy star ratings for homes and such regulations would especially affect McMansions:

The Federal Government aims to introduce, by as soon as next year, mandatory energy star ratings for homes being sold or rented out…

Housing experts said most McMansions would score very poorly on the ratings system, which would be similar to the methodology used to identify the energy efficiency of whitegoods…

There are significant financial implications for owners of these homes – and most older dwellings which are also likely to rate lowly.

Owners would need to either spend up on going green or face the prospect of a lower sale price.

This is one way to push homeowners to improve the efficiency of their homes. This isn’t terribly surprising considering that many consumer goods or appliances these days are rated along these grounds (from electricity cost to miles per gallon). But at the same time, I can’t imagine these sorts of regulations being instituted in the United States anytime soon unless it was solely limited to new construction.