Gallery: Passive House Debate Heats Up on the Future of the US Standard


When we first broke the news of the split between Passivhaus Institute (PHI) and Passive House US (PHIUS), it was a murky proposition to project what the results would be. That answer has become much clearer in the past months after a series of proposed changes and intense debate within the community. The conversation heated up in the last week as those aligned with PHI asked PHIUS to choose a different name for their certification system from Passive House, and Katrin Klingenberg, head of the American group, got personal in her response. The question on everyone’s mind is: “how much damage does this cause the movement?”

As you are probably aware, Passive House is a rigorous high-efficiency building standard first developed in the US in the 70s and 80s then perfected in Germany. It has come back across the Atlantic as a very specific energy standard with PHIUS leading the charge. The developer of Passive House, Dr. Wolfgang Feist severed the European relationship with the US, which resulted in a cleaved Passive House community.

PHIUS, under the direction of long-term director Katrin Klingenberg, recently unveiled a few tweaks to the standard, which resulted in a heated debate as to what Passive House really signifies. The changes have raised eyebrows – they included a retracted ban on some foams, and now a change in the basic base energy usage for some climates from the 15 kWh per square meter per year protocol. The argument is that the 7 climate zones in the US are much different from anything in central Europe, and the standard should be relaxed a little for cold places, and perhaps tightened for more mild zones.

The proposed change has stirred the passion of the Passive House consultants aligned with PHI, who have introduced a petition asking for PHIUS to renege on their use of the term Passive House, as they feel the change in metrics while using the same name will cause market confusion.  The turf war salvo is the latest move after PHIUS sent cease and desist letters to PHI representatives who were issuing the title of Certified Passive House Consultant and for allegedly using unauthorized email lists. The result is a tangle of personalities and metrics that run counter to the original spirit of a simple but rigorous energy-based building standard.

Perhaps the real confusion hinges upon the fact that the two groups are going after each other by playing so much inside baseball in public forums rather focusing on an anemic housing market that desperately needs the standard(s) implemented. Lloyd Alter from Treehugger puts a Plague on Both Their Passive Houses, and the very public conversation is spilling over in the comments on Green Building Advisor, with Katrin Klingenberg oddly calling out dissenters for their “little or no practical experience”, which simply added heat to a burning bridge.

A public squabble among a handful of participants can potentially hamper the implementation of Passive House, which has put many more folks on edge. PHIUS has historic precedence for changing the metric somewhat, as Europe has a host of Passive House certifying groups which have done the same. PHI has also been keeping a low profile and is gracefully allowing PHIUS to use their core energy modeling software. In the end the debate may be healthy if the result is a greater awareness of the intense vetting of Passive House and the passion and discipline all consultants put into making it a reality – or at worst the debate could completely turn the public off to the building standard.


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  1. 42 August 9, 2012 at 7:58 pm

    PHIUS has as much right to the term passive as does PHI and all materials, construction styles and methods are non proprietary in both. I still don’t understand why any time is invested in this conversation at all, its not the “damage” – imagined or otherwise – that PHIUS needs to recover from, its the damage that all of us are doing to our profession and the goal of reduced energy consumption. For PHIUS to understand the vastly different climate conditions in this country only makes me want to incorporate their standard.

    Americans have a hard enough time understanding energy consumption and the way in which buildings are constructed, with the few in this nation that are truly striving to change that, this discussion of PHIUS vs PHI is a complete waste of time, its too late anyway – my guess is we passed the tipping point in October of 2010.

  2. hayden robinson April 3, 2012 at 7:53 pm

    Andrew, I hope that PHIUS recovers from the controversy and goes on to provide a clear alternative to Passive House. Direct, unambiguous competition would benefit the public and encourage both programs toward their full potential. -Hayden

  3. Andrew Michler April 3, 2012 at 5:52 pm


    You have written eloquently about the need to keep Passive House as a single standard and how confusion will be inevitable as two systems use the same label. My point is that much more market confusion is happening now from both the media coverage of your petition and the resulting reactions to it. Whether it’s your intention or not, it is manifesting as a ‘us vs them’ conversation and calcifying into didactic sides.

    Katrin, Thanks for the information on the origin of Passive House. It would be interesting to know more about its origin and what ‘Passive’ means. That seem to be a missing component of the ongoing conversation.

  4. hayden robinson April 3, 2012 at 1:30 pm

    “Healthful” is in the public domain, but it would be dishonest to market junk food using that term. It is misleading for PHIUS to claim buildings constructed under its weaker criteria as Passive House.

  5. kklingenberg April 2, 2012 at 2:06 pm


    The term passive house was coined in the US and Canada in the 70’s. It has been used in the building science discourse ever since. It is solidly in the public domain and describes a building science principle free for everyone to use.

    Katrin Klingenberg, Executive Director of PHIUS

  6. Hayden Robinson March 26, 2012 at 7:36 pm


    Thanks for the column and this opportunity to comment; I have a somewhat different take on things. To me, the question is not U.S. vs. Germany (the directors of both PHIUS and the PHI are German), or even PHIUS vs. the PHI. No one questions that the Passive House standard has been developed, administered and refined by the PHI (headquartered in Germany) for over twenty years, or that the PH standard is used by hundreds of professionals across the U.S. There are a number of certifying organizations, licensed by the PHI, offering Passive House certification in this country. Until recently, PHIUS (headquartered in Illinois) was one of those competing agencies; however, it is no longer accredited by the PHI (as you might imagine, different people have different stories about how and why that came about). PHIUS has continued as an unaccredited Passive House certifier, but has recently announced plans to become not just a certifier, but also an independent standards organization. Most parties seem to applaud PHIUS’s initiative in developing its own standard; the controversy stems from the organization’s plan to claim its standard as Passive House (changed to lowercased in order to infer genericness), while establishing less-than-Passive House performance criteria in some climate regions. Creating a new service and referring to it by your competitor’s name is not competition, it’s appropriation. The resulting confusion and controversy would hurt everyone, not least of all, PHIUS, which would risk marginalizing itself as controversial and “not really Passive House”. I hope that PHIUS will distinguish its programs by using a different term and allow them to succeed on their own merit.

    Hayden Robinson, AIA

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