Passive house is a fairly new word. This recent evolutionary step in building technology comes from Austria, but many of the concepts are ancient. The basic idea is to insulate really well and eliminate random air leakage and thereby require way less heating energy. Ideally all the heat needed will be generated by occupants, their computers and light bulbs, and the sun.
Pretty simple, right? The devil is in the details. Real Passive Houses also must pass a performance test to prove they actually work.
Nabih Tahan was an innovator on the west coast. The New York Times published an article about Passive Houses a houses in 2008 that mentions his Berkeley California renovation project.
Unfortunately, Nabih’s house failed the blower door test for leakiness, so doesn’t actually qualify as a passive house, but he has measured his energy use over the last two years and it performs extremely well. He had to install electric baseboard heaters to satisfy the building code. He rarely turns on these heaters, but since electric heat is inefficient, (a lot is wasted in transmission) his “source energy load” is slightly over the Passive House requirement. He thinks that he would have qualified if he had used gas heaters.
Here is a picture of Nabih’s Air to air heat exchanger (energy recovery ventilator) from Ultimate Air:
The guy in the picture designed and installed the system. His name is is George Nesbitt, and he has a company called Environmental Design-Build.
Nabih installed redwood rainscreen siding. I think it was made out of the old siding, milled into flat slats. His window details are pretty nice:
I am curious what finish Nabih put on the redwood siding. It looks nice. I also wonder how often he has refinished it.
Most normal people do not install unpainted wood on the outsides of their houses these days. The average american likes to spend their time doing a lot of things other than maintain their houses.
I spoke to Nabih yesterday. He told me that he used a Sikkens exterior redwood color stain, probably semi-transparent. It actually seems to be holding up pretty well.