Passivhaus is known as the world’s leading energy efficiency standard for buildings. It drives building energy consumption down as much as 90%. This means paying very close attention to how a building is designed, detailed and constructed to ensure energy is used efficiently and not wasted. It means undertaking very detailed energy and performance modeling during the design process. This can all seem a bit complicated and geeky, so why not leave it to the geeks who love this kind of thing? And only Treehuggers are so into saving energy aren’t they? Actually, no. Here are three reasons why you should care about Passivhaus: Climate Change, EU legislation, and because you can make a difference.