What does one look like? What is Its Real Message of the Passivhaus? No, it is not a bunker, i.e. a house without windows to retain energy – to the contrary…the photo shows a recent winner.“Passivhaus” is among the Holy Grails of green building. Yet so much confusion exists around the term and the concept. Many homeowners associate it with renewable energy sources like solar and wind technology. Not quite – though it can be a part of it in cold climates.
Passivhaus is a construction concept based on the notion that NO active heating system is needed when a home has a super insulated building envelope – even in the depth of winter!
It is not exactly a new concept since the Passivhaus Institut in Darmstadt, Germany has been promoting this approach to building for 20 years. Similar to LEED IG Passivhaus offers a certification program.
While better insulation methods, more energy efficient windows, etc. may be installed to existing homes the Passivhaus Institut folks admit that effectively a Passivhaus can only be created in new construction, as the Passivhaus relies on an orchestration of building materials and technologies.
While walls, roofs, windows and foundations receive much higher insulation another critical element in a Passivhaus is its air filtration system. Heat from exhausted air in the home is being reclaimed and mixed with fresh air brought in constantly from the outside. This ensures a comfortable living environment and avoids mold and other health hazards.
In cold climates the standards for a Passivhaus are slightly expanded: here they allow for the addition of a backup heating unit, which is connected to the air-infiltration system. In other words, again no freestanding heating system exists.
What can we learn from the concept of a Passivhaus?
•There are great advances in building materials that can improve the quality of our lives while reducing our overall energy consumption
•Materials need to be considered as an orchestration
Since there is a general trend to increase energy efficiencies in our building codes around the Nation, I hope experts in building departments understand the importance of a more comprehensive approach instead of the oversimplified dictates of R-values, for example.
It is what has already led us to trouble from increased insulation applications without simultaneously installing proper ventilation and air supply systems. Trapping radon in homes, mold build-out, condensation/rot problems are familiar early warning signs of less than understood building material dictates!
The understanding that one building material affects another is perhaps the most important lesson of the Passivhaus!