More than Passive

I spent last week in Sweden at the Architecture for Necessity conference at the Virserums Museum and had the great pleasure to spend time with famed Austrian architect Walter Unterrainer. Although he is introduced to me as “one of the world’s great Passivhaus experts” (and having designed over 100 built Passivhaus homes, he has earned this title), Walter is quick to respond saying that is not the title he wants. He clarifies in our conversation as well as during his very compelling presentation the next day. While Walter commends the Passivhaus intentions, he says that it is about more than that. It is about good design. “Designing a Passivhaus is easy. But we need to make sure we are designing good Architecture as well.” It is much more than just calculations and scientific numbers. “Good architecture is not a scientific result.” His message resonates strongly, as this is a fear of green rating programs in general (whether it be LEED, or other), that some architects will simply follow the checklist and not innovate or design.

Unless you have been living in a cave the past few years, most likely you have been hearing a lot about Passivhaus, which is an ultra-low energy standard originally conceived by Wolfgang Feist. The Passivhaus Institute defines it as, “a building for which thermal comfort can be achieved solely by postheating or postcooling of hte fresh air mass, which is required to fulfill sufficient indoor air quality conditions – without a need for recirculated air.” Passivhaus is not only a proven route towards net zero, but a green building standard that routinely outperforms LEED in energy efficiency, as it is based on a performance-based system. In order to meet the Passivhaus Standards, these are typically the suggested steps:

    -a compact building form, sited to maximize winter solar gains
    -super insulated building walls, floors and roofs
    -elimination of thermal bridging
    -highly efficient windows, dual and sometimes triple-glazed panels with low-e coatings and insulated frame (typically this is wood)
    -Heat Recovery Ventilator (HRV) with an efficiency of 75% or greater
    -makes use of process heat from appliances, lighting and even humans.

While Passivhaus has been predominantly designed and built to date in the colder european countries, it is moving its way into the US, and there are homes being built (again, typically where there are colder winter climates like Chicago and Seattle).

While the Passivhaus requirements outline smart strategies for making homes efficient, Walter reminds us that there is much more than that. For example, if one simply follows the Passivhaus requirements, minimal amount of windows might be designed. However, that can make for a dismal space inside that actually requires more artificial lighting. So, it is a balance of having strategically placed windows to maximize a sense of space, natural light as well as making sure there isn’t too much of the unwanted heat gain and still an efficient envelope. Also, a large part of his work is innovative in terms of how it is constructed. Walter employs various types of prefabrication in his work, mainly as a way to achieve precision in the details, as well as to make sure the construction in the envelope is as free of moisture and weather as possible (which can be a huge problem when building in wet, cold climates). He also incorporates alternative materials like black fabric as the building’s skin, which ends up saving money that can be used for the solar panels. Walter’s projects also include the social aspect as well with his work in multifamily housing (both new and retrofitting).

It was wonderful spending time with Walter and his work, I felt like I met my European cousin. Walter’s work proves that we can have it all: smart, efficient design and beautiful architecture.

3 Responses to “More than Passive”

  1. Stan says:

    This is a great post! I have been increasingly interested in Passive Haus for the USA.

  2. Just to clarify: windows must be triple pained at this point in time to meet the high performance levels needed to achieve passive house standards. Oddly enough, I am just returning from the US Passive Housetraining classes in Seattle.

  3. Chad Ludeman says:

    These are excellent examples of quality modern architecture that also integrates the very stringent Passive House criteria. While this standard is just taking off in the US, unfortunately most prototype buildings are devoid of architectural interest.

    The Europeans have an advantage with many more Passive House components available to them already (triple pane tilt/turn windows, advanced gaskets, affordable exterior window shades…), but we must do better with our designs if this wonderful building standard is going to catch on in the US. Great post. Thanks for sharing the sample images of his work as well. Inspirational.

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