Housing of the future 
Energy efficiency in building is a big subject and it can be applied in many different approaches: passive house, heat pump, forced air circulation. But there are other ideas that work better and do not rely on vulnerable technology - and are not expensive:
- straw
bale construction: can survive more than a hundred years!
- bio-solar house: an improved passive house, with no moisture barriers and no ventilation system - with hundreds of houses built in 20 years