At cocktail parties around NYC, you may hear people using the phrase “passive house” when discussing energy efficient construction.  Here is what you need to know to be in the know:  Passive House is a voluntary, international building standard perfected by the Passive House Institute (“PHI”) of Darmstadt, Germany in the 1990s, with the Passive House Institute U.S., (“PHIUS”), following shortly thereafter.  Passive House encompasses a set of design principles engineered to meet a high level of energy efficiency – and do so cost effectively.  Passive House relies on superinsulation, airtight envelopes, energy recovery ventilation, high performance windows and managing solar gain. While passive building does cost more than conventional building – according to PHIUS, passive building costs 5-10 percent more – both residential and commercial Passive House buildings see an 80-90% reduction in space heating and cooling costs and an increase in indoor air quality.

While both PHI and PHIUS continue to promote Passive House, they now do so separately with differing philosophies.  The core concept of PHI’s Passive House standard, to utilize no more than 15 kilowatt hours per square meter of space per year, is a central point of contention between PHI and PHIUS, as PHIUS contends that the 7 different climate zones across the United States are much more varied than the central European climate and further, that the standard should be relaxed for colder climates and more restricted for mild climates.  Along with other technical and philosophical differences, such as PHIUS converting PHI’s primary design software from metric to English measurement units, this difference in core belief caused PHI to end collaboration with PHIUS in August, 2011.

In spite of the separation between PHI and PHIUS and the resulting fall-out, the Passive House building standard continues to grow in popularity.  Just last fall, New York City Mayor Bill de Blasio announced the release of New York’s new building-focused climate change initiative, which focuses on Passive House as a standard for new construction and retrofitting of older buildings.  This raises a number of questions about what this means for the average NYC homeowner – whether they be in a brownstone, condominium or cooperative building – seeking to construct or renovate a home.  Stay tuned for more on the legal, practical and financial implications of passive building in an urban setting.