On Our Green Journey, We Discovered Passive House

November 13, 2010

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Last week, we had a chance to meet Dr. Wolfgang Feist in San Francisco, where he gave a free public lecture on Passive House at the California College of Arts.  Dr. Feist is the founder of Passivhaus Institut and is on the faculty of civil engineering at University of Innsbruck.  He was on his way to Portland, Oregon for the 5th North American Passive House Conference.  My post is a quick summary of the notes I took from that talk.  Just as a new student may not get all her facts correct, my notes below reflect my current state of enlightenment and ignorance.  OK?  Here it goes –
The Passive House is not an energy performance standard, but a concept to achieve highest thermal comfort conditions on low total costs.  The passive house buildings don’t have a particular look and or follow specific architecture.  The concept can be applied to different types and styles of buildings.  What we found impressive about passive house is the performance.  By following the passive house concept a building built in 1991 in Kranichstein, Darmstadt, Germany was able to reduce the energy consumption of the building by 80%.  The building performance was monitored from 1991 to 2010.  Amazing, isn’t?
There are 5 principles –
1.    Insulation.  Lots of insulation on the exterior walls, roof and the basement ceiling.  In the particular building shown in the case study there was 12-inches on the roof, 12-inches on the exterior walls and 10-inches on the basement ceiling.
2.    Free from thermal bridges.  Basically you want to eliminate the path that heat can flow.
3.    Air Tightness.  Warm air moving from inside to the outside of the building will deposit moisture into the building as it exits, causing problems for the building.  Air tightness of the building is achieved by applying special tapes and testing it using the blower door test.
4.    Energy gain window.  Triple pane windows allow more solar gain and less energy loss.  Note that the solar gain in the winter in central Europe is 1/5th of what’s in the Bay Area.
5.    Heat recovery ventilator. HRV is a quiet, hygienic and efficient device that provides conditioned fresh air to come into the building, providing comfort and reduced radon exposure.  The standard for HRV, by the way, is different between Europe and US.
Today all European countries have passive house demonstration projects.  Passive house demonstration projects are also found in other countries such as Russia, Japan, China, Korea, South Africa, Australia, Antarctica, Chile, Canada and United States.
To learn more about Passive House please visit Passive House Institute US and also the Passipedia site, where passive house information is available to the public and member postings are reviewed by scientists.  

About the Author

Chie Kawahara

Chie is one of the co-creator of Midori Haus. When she is not sharing her stories of transforming an old house and giving tours, she enjoys trail running and hiking.