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PassivHaus Standards for N. America?

GBA Editor | Posted in Energy Efficiency and Durability on

BuildingScience.com has just published an article by John Straube with a critical analysis of the relevance of PH standards for a North American climate:
http://www.buildingscience.com/documents/insights/bsi-025-the-passivhaus-passive-house-standard

His conclusions:

Homes in cold climates (DOE Zones 5-7) that employ:
• minimum R-5:10:20:40:60 enclosure,
• 1.5 [email protected] airtightness or better,
• condensing (>95%) gas furnaces with ECM fan motors,
• right-sized (ASHRAE 62.2) efficient (> 65%, >1.5 cfm/W) HRV’s
• condensing (>92%) hotwater natural gas water heaters
• appliances in the top 10% of Energy Star combined with CFL lighting

deliver total energy and environmental performance that approaches the Passivhaus standard in cold climates. Such houses depart in relatively minor ways from standard North American construction, accommodate a broader range of architectural styles, can be modified easily for different climate zones, and can even be built by production builders.

Achieving the specific Passivhaus target of 15 kWh/m2/yr for heating on site energy use, results in investment of materials and money that often will exceed other less costly and environmentally impactive solutions. Achieving the equally arbitrary 120 kWh/m2/yr has more direct environmental benefits than the heating target, but may best (i.e., with least cost and environmental damage) be achieved using some on-site power generation.

As new clean, local, and renewable energy sources come on line over the next 25 years and become more affordable than current PV prices, it is unlikely that the extreme conservation measures taken by Passiv Haus to meet the specific requirements will be considered an optimal deployment of resources for cold climate housing.

From a point of view of the wise use of capital, the Passivhaus approach in cold-climate zones of North America can often lead to more expensive, less architecturally flexible, and even more energy intensive houses than a more flexible approach that focuses only on the least cost, most durable means of achieving a primary energy use per area target value. Perhaps the most important contribution made by the PH standard to low-energy North American housing is that one cannot simply buy $200,000 worth of PV panels to meet the target, as too many net zero homes have done.

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Replies

  1. Robert Riversong | | #1

    Bump...

    Any thoughts or comments?

  2. John Brooks | | #2

    Robert,
    You may find this interesting
    https://www.greenbuildingadvisor.com/community/forum/passive-house/14647/very-recent-passivhaus-article
    I am slowly realizing that Passivhaus is not perfect or the greatest thing ever.....
    I still however believe there is much to learn from our friends in Europe.

  3. Anonymous | | #3
  4. Robert Riversong | | #4

    Sorry, the Building Science email announcing this article arrived today, so I didn't realize it had already been discussed here.

    I would like to see a rebuttal from Straube to the criticisms of his article. While it appears he may have made some incorrect assumptions or interpretations of PH standards, the defense of PH often appears to me to be more ideological than scientific.

    And I think everyone is missing the primary dysfunction of the PH approach, which is nothing other than taking the isolation of human habitatation from the natural world to its logical extreme. It is the same dysfunction that has created every one of the global crises we face today: a dramatically accelerating separation of people from the web-of-life.

    If the isolation and insulation of humanity from its natural context is the source of our problems, then more of the same surely cannot be a solution.

  5. Andrew Henry | | #5

    Robert

    I don't think the intent of PassivHaus was to take "the isolation of human habitatation from the natural world to its logical extreme".

    I will the first to agree with you that our present societies have a severe case of "Nature Deficit Disorder" but I doubt Feist and his colleagues set out to increase our separation form nature. Besides achieving the kind of load reduction that PassivHaus sets out to do should have a pretty substantial impact on reducing natural habitat destruction that would result if we just built slightly better houses and made up the heat loss with renewable energy.

    Yes you can put some renewables on roofs and in brownfields but most of the major wind and hydro developments require a whole lot more generation and transmission infrastructure, much of which will be greenfield development. All this renewable generation and transmission capacity will also require a lot more copper whose extraction is hardly "green".

    Load reduction from my perspective is by far and away the best value when it comes to reducing our impact on ecosytems. For me, and this is philosophical, Passive House achieves many things by focusing on reducing a building's load, the most important of which may be that it does the most to protect Natural systems.

    As an example I live in Quebec, we have a lot of Hydro, renewable yes, but the five biggest Hydro projects in the province have submerged an area the size of Lake Ontario. Submerging that much land and turning river ecosystems into reservoirs has a very profound impact on natural systems. Would there have been a need to build that much capacity, and it's resulting environmental damage, if society had decided to reduce energy loads instead of making up for poor design with energy?

    Passive House may leave a little more nature for us to help us overcome our "Nature Deficit Disorder". I say will because we may just turnaround and take the money we save and fly off to a sunny spot in the winter. The curse of Jevon's Paradox as Martin Holladay wrote about.

    Andrew

  6. Robert Riversong | | #6

    Andrew,

    I didn't in any way suggest that PH was developed with evil intent. All our technological "improvements", since the first stone tool, have been created with the intent to make our lives in some way better or easier or safer or longer - but always at the expense both of Nature (the wild, the other) and of our own connection to the web-of-life (our innate spirituality, our soul).

    Nor did I suggest that consuming more "alternative" energy is any better a "solution", since that too is based on the same consumptive, technological (control) paradigm: the next generation of technology will correct the consequences of the last generation of technology.

    No one can dispute that PH has taken the modern "green" trend toward more and more efficient building envelopes to its logical conclusion. And, if that is true, then it must also be true that PH is the epitome of the same trend - begun when we first "tamed" fire - of creating a more and more separate human space isolated from the natural space.

    Increasing isolation from the ground of our being and our sustenance can never be a solution to the nature-destroying separation that has brought us to the brink of ecological and spiritual destruction. Doing more of the same and expecting different results is the very definition of insanity.

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