More Media Coverage of PHI/PHIUS Split

Ecohome, a magazine of the American Institute of Architects (AIA), continued the media coverage of the decision by the international Passivhaus Institut to end its contractual relations with the Passive House Institute US. The magazine featured a quote from Gregory Duncan and a rendering of his proposed Passive House project in New Orleans.

Gregory Duncan, a New York City architect with credentials from both institutions, says despite the organizations’ difference of opinions the benefits of building to the Passive House standard remain unchanged: “Lower utility bills, reduced noise, and better indoor air quality are just a few,” he points out.

Meanwhile, members of New York Passive House are still busy designing and building Passive House projects in Harlem, the Lower East Side, Brooklyn, upstate, and elsewhere in the region.

Brute Force

My colleague in the Pacific Northwest, Mike Eliason, at Brute Force Collaborative, has shared his perspectives on the recent split between the Passive House Institute US (PHIUS) and the international Passive House Institute (PHI), based in Darmstadt, Germany.

As an architect with credentials from both institutions, I hope the two parties can reconcile and work together in the future. Meanwhile, the benefits for homeowners and developers of building to the Passive House standard remain unchanged. Lower utility bills, reduced noise, and better indoor air quality are just a few. And for a variety of reasons, this energy-efficiency standard works especially well in New York City.

If you follow my tweets (@DuncanArchitect), you know that I sometimes spend my Sunday mornings reading German Forschungsberichte from PHI instead of going to brunch. This particular research report detailed six years of monitoring the energy use in a school built to the Passive House standard. The report confirmed scientifically that a frost skirt can allow for less sub-slab insulation. Short term monitoring and lab experiments had previously suggested that this was true, and these findings are already incorporated in the PHPP energy modeling software. Real-world monitoring to confirm the assumptions made in energy modeling software is important, and I’m glad to see that this monitoring validates the accuracy of PHPP.

The bottom line is that the scientific basis of Passive House is strong and the rift between PHI and PHIUS won’t prevent people from being able to have a certified Passive House building with lower utility bills, reduced noise, and superior indoor air quality.

Email Greg Duncan at for more information.

Multifamily Passive House Buildings in New York

The most obvious benefit of the Passive House standard is a dramatic reduction in energy costs. Using the Passive House design methodology and energy-modeling software, architects can save building owners up to 90% on heating costs compared to a typical existing building. In addition buildings built to this standard have superior thermal comfort—warm in winter and cool in summer with no drafts. A side benefit of using high-performance windows and air sealing is reduced noise from the street and from neighboring apartments. The proper architectural details can provide for acoustic insulation and energy efficiency.

Rental Buildings

Due to the expense of submetering and market expectations, owners of multifamily rental buildings in New York usually pay for heating their tenant’s apartments in addition to the common areas. By law landlords are required to provide heat between October 1 and May 31. This can be a significant expense, so developers often ask their architects to design energy-efficient buildings.

Condo Buildings

Tenants in condominium buildings often have their own heating equipment in the unit and are responsible for their own heating bills. One of the reasons condo buyers are attracted to green buildings is that they can save a lot of money on their utility bills. If the energy savings are significant, as with a certified Passive House building,  the developer’s initial investment will pay off with a higher sales price.


As an architect who has worked on townhouses in Brooklyn and Queens, as well as larger apartment buildings in Manhattan, Gregory Duncan understands the potential this type of building has for huge increases in comfort and energy savings. See our article on Passive House in New York City which explains how this green building standard is in many ways easier to achieve in New York than many other places.

Of course, the Passive House energy-efficiency standard applies to commercial and single-family houses as well. So, no matter what building type you are planning, a Certified Passive House Designer can help you make it better.

Email Greg Duncan at to get started.