Not bad but there were plenty of passive solar houses built before 1991 though. I even did project in High School on Passive Solar homes in 1981.
We built ours in 1996. 2400 sq ft & we burn 2 cords of wood in Zone 4 US. No backup heat source. I get cranky if the temp gets below 67°F. There are days when it's a little cool in the house but a fire would be too much. Our designer told us to bake a pie or have friends over. It works.
My project thread Agriculture collects solar energy two-dimensionally; but silviculture collects it three dimensionally.
This is one of the bigger problems with passive house, its name implies passive solar design but it is not synonymous and leads to plenty of confusion. This thread and video probably belongs in the green building thread more than the passive solar thread.
The video is an outline of the principles behind the german born building certification. http://www.phaus.org/home-page At Green Building advisor, they tend to spell it differently to help differentiate the two, spelling it more german "Passive Haus". The video mentions Passive Solar Design is used to help heat Passive Haus built homes but from my understanding, you can have a Passive Haus that is not a Passive Solar Design. As long as a building pays attention to air leakage, insulation and fenestration performance, then the home does not need to include passive solar design to achieve 90% energy reductions.
Adding to the confusion, there is now a North American split from the Germans. http://www.passivehouse.us/passiveHouse/PHIUSHome.html I dont keep up with all the political happenings in this area but what's important is that this movement is gaining popularity much quicker than most would have thought possible. The modeling software, repeated results and measurable improvements make for a compelling green building strategy.
"If you want to save the environment, build a city worth living in." - Wendell Berry
Brian Knight wrote:This is one of the bigger problems with passive house, its name implies passive solar design but it is not synonymous and leads to plenty of confusion. This thread and video probably belongs in the green building thread more than the passive solar thread.