Today’s brief blog — a departure from my usual practice of writing in-depth articles — was inspired by a recent editorial by Richard Kadulski, the editor of a Canadian newsletter called Solplan Review.
In the March 2014 issue, Kadulski wrote, “I have had discussions with some designers and builders that have set out to build in accordance with Passive House principles. When I questioned them, and suggested alternatives that might be easier to build or be more economic, the answer invariably comes back that it’s not an acceptable Passive House detail.
“If Passive House has laid it out, it’s the gospel, and don’t bother with anything else. And don’t bother questioning whatever quirks have been built into the criteria or the software because it cannot be challenged.
“Like converts to a new religion, they seem to lose sight that there are many ways of achieving high-performance, sustainable building.
“If we’re going to make progress to achieve truly efficient, sustainable and net-zero construction buildings, we need to be able to entertain new ideas and take advantage of new tools and materials. It’s great to get enthusiastic buy-in from new participants who will champion the cause — these are vital to help spread the word. But we need to be careful not create a new religion with a set of dogmas that cannot be challenged.”
Rigor vs. flexibility
Any group that sets out to write a standard has to address the inevitable tension between rigor and flexibility. Almost by definition, rigorous standards tend to be inflexible.
Some standards are prescriptive standards — that is, they tell builders exactly what they need to do, step by step — while other standards are performance standards — that is, they set goals that builders much achieve without telling them how to get there.
The Passivhaus standard is a performance standard, so Kadulski’s encounter with Passivhaus rigidity doesn’t stem from the prescriptive vs. performance tension. Other factors are at work, including the fact that the Passivhaus standard leads designers down a path that often results in methods that aren’t cost-effective.
For designers who are used to following a performance-based path rather than a prescriptive-based path, the usefulness of including a photovoltaic (PV) array to arrive at net-zero performance seems obvious. The fact that the Passivhaus standard (so far) forbids designers to use PV arrays to achieve their goals (including the all-important 15 kWh/m2*yr goal) is a significant source of the tension that Kadulski alludes to.
Will the new North American standard be more flexible?
In Darmstadt, Germany, Dr. Wolfgang Feist recently declared that “the fundamental definition of a Passivhaus has been validated and will not be altered.”
In spite of the apparent rigidity of Feist’s stance, he simultaneously announced that three new standards are under development in Darmstadt: two that are more stringent than the existing Passivhaus standard, and one (a proposed standard called the “Energy Conservation Building” standard) that is less stringent.
Meanwhile, changes are afoot in North America. According to Katrin Klingenberg, the executive director of the Passive House Institute U.S. (PHIUS), “The PHIUS Technical Committee, a volunteer body based on modified consensus and comprised of international building science experts and North American passive house practitioners, embarked on the plan to identify a methodology to generate new passive standards for all climate zones.”
Will the PHIUS committee’s new passive house standards provide more flexibility to North American designers? Time will tell.
Martin Holladay’s previous blog: “What Should I Do With My Old Windows?”