"It's extraordinary that the Lib Dems are still claiming that they will protect green spaces when they plan to concrete over our countryside with thousands more houses on green field sites, " she said.

BBC: Nick Clegg

The existing law aims to make California's cars, trucks, houses and appliances more efficient, and to foster green industries.

ECONOMIST: Ballot initiatives

The concept has been around for several years, but until now most Green Houses have shared a campus with sister care facilities, often large, more traditional nursing homes.

FORBES: How Senior Communities Can Connect with Their Neighbors