Passive Houses Get Good Graphic Explanation
New York Times
The New York Times has a great graphic explanation of the principles of the Passive House, "airtight buildings that use heat from appliances and even the occupants' bodies for warmth." The Times notes that while they are popular in Germany and Scandinavia, they have not caught on in the US, where it seems that the "green gizmo" approach of adding photovoltaics and heat pumps rules over simplicity and efficiency. (and, admittedly, air conditioning is a bit more common)
Passive House, Voralberg, Austria, Passive House Institute
But it makes a lot of sense to design a house that doesn't need a lot of technology. The Passive House idea is really simple:
1. Insulate it. Like 12 inches of the stuff in the walls, sixteen inches in the roof, six inches under the slab.
2. Site it well, to get passive solar gain. Design the overhangs and trellises to stop solar gain in summer.
3. Keep the design relatively small, simple and tight, minimizing exterior area and complicating jogs.
4. Install a heat recovery ventilation system to provide constant fresh air; you are going to need it in a house that is so well sealed.
New York Times
The New York Times describes a heat recovery wheel heat exchanger; others work on a labyrinth principle with no moving wheel, but a heat exchanger. In warmer climates one might use an enthalpy wheel, which transfers moisture as well as heat.
Smith House, Passive House Institute
As I noted in our discussion of the Smith House by Katrin Klingenberg in Urbana, Illinois,
So how simple is that? a tight, efficient plan + careful siting to max out the passive solar + lots of insulation gives you an almost zero energy house. This ain't rocket science, it is just good design.
More in Planet Green on passive design and low tech solutions:Low-Tech Tips: Tune Your WindowsLow-tech Tips: Get the Roof Overhangs RightLow-tech Tips: Keep Cool with AwningsGet a Heat Recovery Ventilator if You Seal Your House Up Tight