You wouldn't buy a car without knowing what kind of gas mileage it gets. But when it comes to homes, we don't pay as much attention to energy efficiency. We should. Not only do buildings account for more than a third of North America's carbon emissions, having an efficient home can also save you money on utilities bills. With solar panels or turbines, a house can even make you money.
Over in Europe, they're trying to make sure homebuyers know whether they're getting a lemon. New legislation in the European Union will require that, starting in 2012, every home that goes on the market comes with a letter-graded Energy Performance Certificate. Now people will know if their new house will be impossibly expensive to heat in our Mad Max future. And home sellers might do an energy audit while they update the kitchen.