Passivhaus: Too Rigid and Inflexible for America?
Ettel House, Maschin Architectur
TreeHugger has written Forget Energy Star and LEED, The Real Standard for Green Building is Passivhaus, generally having nothing but good things to say about it. But Alex Wilson, who has been writing about green building since 1992, looks at it without my rose-coloured glasses and has a few interesting comments.
Passivhaus projects in North America. source: buildinggreen
Wilson notes that the Passivhaus really had its origins in America; Wolfgang Feist, the developer of the Passivhaus standard, got the idea from Amory Lovins and the super-insulated designs from the seventies. Wilson writes:
Passive House is based on Lovins' concept of reducing investment through energy-efficient design. "By dramatically increasing the energy efficiency of a building, the HVAC systems can be radically simplified upon reaching a certain level of efficiency," wrote Feist.
The problem, according to Wilson, is that the standard is developed for moderate European climates which are rarely extremely hot or extremely cold. In North America, the temperatures can be far more extreme. His suggestions:
In very cold or very hot climates, relax the heating and cooling requirements while maintaining the total primary energy consumption limit. In climates with very high heating or cooling loads, the Passive House standard right now may be too difficult to achieve.
Katrin Klingenberg's house in Urbana, Ill: small, boxy and very efficient
Eliminate or minimize the bias against small houses. Because Passive House standards are based on floor area, larger houses can use more energy and meet the standard, and it's harder to certify small houses.
(This caught me by surprise; most passivhaus designs we have seen have been small and boxy. But that appears to be due to the European tendency to live in smaller spaces, and due to the cost of construction of such highly insulated walls and such high performance windows. But in fact the standard is biased against smaller homes)
Passivhaus renovation in London: It's like building a house within a house
Relax the Passive House standard for existing buildings. Solving our climate crisis will require a huge focus on existing buildings, and a strong standard like Passive House could be a tremendously important tool in getting there. But it's just too hard to achieve right now.
Good points all. Read Alex Wilson's shorter blog version here He has removed the pay wall from BuildingGreen's extended version entitled Passive House Arrives in North America:
Could It Revolutionize the Way We Build?
More on Passivhaus in TreeHugger
Forget Energy Star and LEED, Green Building is Passivhaus
Passive Design and Passive House Mean Two Different Things
Good Green Design Doesn't Have To Be Expensive: The M&M; House
A PassivHaus Renovation: Heritage Meets Energy Efficiency
A Passiv Haus in Urbana, Illinois