The Passivhaus Institut (PHI) of Darmstadt, Germany, severed ties with the Passive House Institute US (PHIUS) of Urbana, Illinois, in an open letter released on August 17, 2011.

The letter from Passive House co-creator Dr. Wolfgang Feist of PHI alleged, among other things, that PHIUS, which had been PHI's sole U.S. affiliate, had issued an official certification to a house that was not up to the Passive House standard — one of the world's toughest when it comes to energy efficiency.

A few days later, Katrin Klingenberg, executive director and co-founder of PHIUS, fired back, denying the charges and leveling allegations at PHI, including breaches of contract and business ethics.

Beyond the specific accusations, the dispute entwines the direction and pace of the growth of the Passive House program in the United States, where the standard officially arrived in the late 2000s. Elements of the clash include cultural differences between Feist's German headquarters, which operates as a business, and the U.S. institute, which, like the U.S. Green Building Council, is a nonprofit group.

Feist and Klingenberg are both are known to be tireless advocates of Passive House, and they are also both known as difficult to work with. The U.S. schism is not the first struggle Feist has had with PHI affiliates outside of Germany. Klingenberg, meanwhile, has ruffled feathers in U.S. green building circles with a personal style that some have found blunt and remote.

Passive House

Inspired by the superinsulated homebuilding movement that took hold in the United States in the 1970s, Wolfgang Feist and Swedish professor Bo Adamson came up with the Passive House concept in the 1990s, creatively applying accepted building physics methodology to address ventilation, air quality, and mold problems that had stymied the first generation of superinsulated houses.

A Passive House-certified building — which can be any kind of structure, not just a residence — uses only about 10 percent of the energy needed to heat and cool a conventional structure built to the 2009 International Energy Conservation Code. The huge energy savings are achieved through an airtight building envelope with heat-recovery ventilation, elimination of thermal bridges, and lots of insulation.

With 90% energy energy savings over new buildings built to code, the performance level of Passive House buildings is currently unique among available green building and energy certification systems in a very important way.

Only Passive House buildings are required to perform today at the energy efficiency levels that we can expect for all buildings sometime around 2050 — in less than 40 years.

Putting it another way, nearly every new building that is built today to less than Passive House standards can readily be predicted to become obsolete, in terms of energy performance, in less than 40 years.   >>>