Unlike profligate North Americans, in Germany they have gone from a standard house's consumption of fuel oil of up to 30 litres per square meter to "three litre houses" to "passive" (max 1.5 litres per square meter) to "positive energy" houses that give back more than they consume. Everybody is doing it; more than six thousand have been built. Architects compete to design the most energy efficient homes. Houses and apartments are being renovated and upgraded; The government gives subsidized loans to encourage it. It isn't even hard or high tech- lots of insulation, good siting for solar gain, "The heat released by small appliances and the body heat of the inhabitants -- which amounts to no less than roughly two kilowatt hours per person and day -- is largely sufficient. Automatic ventilation -- with a built-in heat retention system, of course -- ensures that the rooms don't get too stuffy." Their homes cost a lot more per square foot that North American ones do, so logically they build fewer square feet. What could be simpler?
We don't need to reinvent building technology and develop new expensive sources of energy, we just have to remember that Conservation is the World's best energy source, and build half as much twice as well.::Der Speigel