New York Developer’s Guide to Multifamily Passive House Certification

New York Passive House has published a great free guide to certification of multifamily Passive House buildings.

One of the example projects is the 68-unit affordable senior housing building that Duncan Architect is consulting on in Corona, Queens. HANAC

If you’re interested in high performance multifamily construction, download the guide.

With Passive House as an identified incentive by New York State Homes and Community Renewal for affordable housing financing, and funding organizations like the Community Preservation Corporation also recognizing Passive House, it is important to demystify the process and provide support to those developers interested in pursuing Passive House construction.

The Guide provides 8 clear steps most useful in making a successful project, 7 important reasons to get your development project certified to the international Passive House Standard, and a succinct outline of the certification protocol to get you across the finish line.

White House announces Passive House initiative in New York

President Obama announces new actions to bring renewable energy and energy efficiency to households across the country, advancing clean energy technology innovation, cutting energy bills, and creating jobs.

The White House press release includes an initiative of New York State Homes and Community Renewal to add Passive House certification to its RFP for preservation and creation of high quality affordable multifamily housing. Passive House is a proven method of providing comfortable, healthy, energy-efficient buildings that complements other programs, such as LEED. Certifying to the international Passive House Standard provides proof that your building is among the best performing in the world.

Duncan Architect’s experience in multifamily Passive House design would be a great addition to teams applying for funding through the New York HCR RFP. Contact for more information.


June 2015 Passive House Events in the New York Region

June, 2015, is a big month for Passive House events in and around NYC.

Following the NYC mayor’s office’s report, One City Built to Last, which calls for Passive House as part of the solution to reduce carbon emissions 80% by 2050, interest in the Passive House Standard for building comfort and energy efficiency has exploded.

June 1: Seal it Tight, Make it Right – AIA Event

June 2: Passivhaus: Lessons from Europe – A Building Energy Exchange Event

June 5: Facade Performance 101, including an overview of the Passive House Standard

June 8-12: Certified Passive House Tradesperson Training in NYC by Passive House Academy with NYSERDA funding

June 9: Advanced Passive House Consultant Training – PHILADELPHIA

June 11: NY15 Conference and Expo – Built To Last: Passive House

June 12: Advanced Passive House Consultant Training – New York City

June 15: Passive House Meets Net Zero – Online/Live Streaming


Passive House Engeldamm in Berlin

Passivhaus Engeldamm (PHED) is a mixed-use multifamily and office building in the Luisenstadt neighborhood of Berlin. Glass and concrete may seem like unusual materials for a “green” building, but it shows the design freedom of the Passive House Standard. The apartment building faces a beautiful park where the Berlin Wall used to divide the city. Unfortunately, economic divisions continue, and anti-gentrification protesters vandalized the building a few years ago.

The concrete balconies have a nice texture from the OSB formwork.

Passivhaus Engeldamm Berlin

The building’s architects, Scarchitekten, have their offices on the ground floor.Passivhaus Engeldamm Berlin

Growth of Passive House Standard in New York


NY Times launches Passive House above the fold in Real Estate section

New York City’s rapid embrace of the Passive House Standard for comfort, health, and energy efficiency made The New York Times cover story in its Real Estate section on Sunday, March 29, 2015.

Duncan Architect is the Passive House consultant for a senior residence with a pre-K on the ground floor. This project is one of those featured in the Times article.

 A social services organization, the Hellenic American Neighborhood Action Committee or Hanac, has also jumped on the passive-construction bandwagon for its eight-story 68-unit senior housing development, to be completed in Queens in summer 2017, said John Napolitano, Hanac’s director of community development and planning.

Part of the allure of passive house is the ability to withstand some of the effects of power cuts, he said.

“We’ve had several blackouts, and keeping the seniors in their homes during those periods, in an environment where we can maintain thermal controls in the units for a period of at least five days without disturbance, resonates with us,” Mr. Napolitano said. “We can do that with passive house.”

“The Passive House in New York” NY Times

New York Passive House reviewed the article

NY Passive House (NYPH) is particularly proud of this article because it features a range of work by NYPH members, including:  Stephen Lynch of Caliper Studio, 255 Columbia Street by Ben Igoe of JBS Project Management & Sam Bargetz of LoadingDock5, Steve Bluestone of the Bluestone Organization, HANAC senior housing with consulting by Greg Duncan of Duncan Architect, and Michael Ingui of Baxt Ingui Architects.

and followed up with more information about the upcoming conferences in Germany and New York City. Greg Duncan will be going to the International Passive House Conference in Leipzig, Germany on April 16 and the New York Passive House Conference on June 11.

Duncan Architect is glad to be able to help people jump on the “passive-construction bandwagon,” especially on a project like the HANAC senior housing that will be such a benefit to the community in Corona, Queens.




Passive House Books

Passive House is the world’s leading comfort and energy-efficiency standard for all types of buildings.

The Duncan Architect Passive House Bookstore has books for general as well as expert audiences.

I just added a link to Mary James’s 2010 book Recreating the American Home: The Passive House Approach. I reviewed her newer book, American Passive House Developments, stating:

“Passive House, a method of building that traces its roots to American pioneers such as Amory Lovins, is the world’s leading energy efficiency standard for buildings. It applies to all building types, allowing people to save energy in their homes and workplaces without sacrificing comfort. Now, Mary James, a leading voice in the American Passive House movement, lucidly articulates that Passive House is not just a residential phenomenon by showcasing a sampling of intriguing current projects including multifamily developments, commercial kitchens, and brownstone renovations.”

For Passive House designers, I would recommend Sarah Lewis’s book PHPP Illustrated: A Designer’s Companion to the Passive House Planning Package for an in-depth guide to the energy modeling software that is the basis for Passive House design.

For great photographs and accessible information, I would recommend Julie Torres Moskovitz’s The Greenest Home: Superinsulated and Passive House Design. Disclosure: she’s a friend of mine and one of our projects is featured in the book.

For those interested in the history of passive solar approaches to architecture, I would recommend Anthony Denzer’s The Solar House: Pioneering Sustainable Design. It includes “the work of masters of twentieth-century architecture such as Richard Neutra, Le Corbusier, Frank Lloyd Wright, Paolo Soleri, Louis Kahn, Pietro Belluschi, Edward Durell Stone, and Harwell Hamilton Harris, and continuing with more recent innovations like the German Passivhaus movement….”

New York State Green Building Conference



The 2015 NY State Green Building Conference will include a presentation by Gregory Duncan about multifamily buildings designed to meet Passive House criteria.


“Passive House” describes a comfort and energy-efficiency standard for all building types. This presentation will focus on the design of multifamily buildings in our region to meet the Passive House criteria. The scale and form factor of multifamily buildings relative to single-family can be advantageous, while urban site constraints are often challenges that must be addressed. The audience will learn the advantages of a “fabric first” approach to design that emphasizes the importance of the building enclosure for high performance and thermal and acoustic comfort.


Gregory Duncan began his architectural career with an internship in Germany, the birthplace of the Passive House movement. Since 2000 he has primarily designed midrise multifamily and mixed-use buildings in New York City and surrounding areas. In 2009 he became a founding member of New York Passive House and is currently a Vice President. His Passive House consulting work includes the first certified Passive House retrofit in Connecticut.


This just in!

The program for the 13th Annual New York State Green Building Conference has been approved for Professional Development Hours (PDHs) for engineers, Continuing Education Credits (CECs) for landscape architects, and AIA Continuing Education System Learning Units (AIA CES LUs) for architects. A participant can earn a maximum of 8.0 PDHs, 5.0 CECs and 8 AIA CES LUs by attending the full Conference. (Some presentations are still under review) Please see the agenda for more information. LEED Professionals may earn up to 10 GBCI CE Hours by attending the full Conference. You may now self-report unlimited education hours toward your credential maintenance! (Sign in at sessions required to receive certificate.)

Big Changes for New York Buildings to Address Renewable Energy and Resiliency


New York is preparing for the potential closure of the Indian Point nuclear power plant by investing in demand reduction, on-site energy production, and energy storage. The Combined Heat and Power (CHP) Acceleration Program from NYSERDA is part of this effort.

CHP provides resiliency in case of power outage. Because the equipment runs 24/7, it is likely to continue operating during an emergency, as long as natural gas supply is not disrupted. Backup generators, on the other hand, risk not starting when they are needed and generally do not have the fuel to operate for days at a time. For commercial buildings over 50,000 square feet (5000 square meters), multifamily buildings with more than 200 units, and buildings that have a high hot water demand, CHP is economical, especially with state incentives. In smaller buildings with Passive House levels of efficiency, however, it may make more sense to disconnect from the natural gas connection to avoid fossil fuel use. Providing hot water using direct electricity is more efficient within a renewable structure.  [2014 PHI Conference Proceedings P. 651] Domestic hot water tanks heated by air source heat pumps can act as energy storage for a renewable smart grid infrastructure.

More information about installing CHP microturbines in NYC buildings.

Currently CHP relies on natural gas supplied by utility companies. However, there is a potential synergy with a new technology called Power-to-Gas (P2G). P2G is useful for seasonal storage of surplus renewable energy. With P2G the amount of methane gas required for a typical house would be about 3.5% of the amount of natural gas equivalent (fossil energy) currently consumed. [2014 PHI Conference Proceedings p.641] Why not use biogas? Biogas is problematic because it requires a lot of agricultural and forest land that could otherwise be used for food, raw material, and transportation fuel.

Renewable energy is likely to continue its fast growth. In fact, the investment bank UBS sees residential PV as a huge growth market in the near future, even though utility-scale PV is less expensive per installed peak watt. As onsite PV energy production becomes more common, there will be a challenge with overproduction on sunny days and the need to use energy from storage at night, especially during cold winters. A change to New York State’s utility structure may be needed to address the cost of renewable energy storage and transmission. In addition to energy storage, one solution is to use onsite PV energy as much as possible before exporting it to the grid. This has been called—a little inelegantly—self consumption. German architect Kay Künzel presented his self-consumption strategies at a New York Passive House presentation on February 27, 2014. His home automation system timed certain appliances to run during the day to take advantage of direct PV energy. Another self-consumption strategy is to use DC power as much as possible to avoid the DC-to-AC inverter losses.

Solar panels on vegetated roof of Etrium Passive House office building near Cologne. Photo by Greg Duncan

Solar panels on vegetated roof of Etrium Passive House office building near Cologne. Photo by Greg Duncan

New York City recently passed the Zone Green amendments which make installation of solar panels easier, although in order to qualify for New York property tax rebates for installation of solar panels, you will need to have a registered architect or engineer file with the Department of Buildings. To calculate the photovoltaic potential in your location and to get information about incentives, use the PV Watts calculator.

Duncan Architect can help you create buildings that are energy-efficient and resilient with onsite renewable energy where feasible. Email for more information.


Passive House Institute to Include Renewable Energy in New Ratings

The Passive House Institute has announced [PDF] that it will start rating buildings that produce renewable energy while meeting the clearly defined Passive House Standard. In order to do this, PHI had to reexamine the calculations for primary energy. PHI uses the term primary energy to refer to what the US EPA calls source energy which you may be familiar with for Energy Star ratings. I’ll use PHI’s terminology in this post. See the Energy Star Portfolio Manager Technical Reference [PDF] for national source energy ratios for the US and Canada. These ratios depend on the mix of electricity generation. EPA chose to use national averages instead of local or electrical grid ratios. The choice of a “correct” primary energy ratio is complicated and not apolitical. For example, some people may disagree that burning coal on site is equivalent to onsite PV (both have primary energy ratios of 1.0 per EPA).  And the ratios are constantly changing. When designing buildings that will last decades, should we use past primary energy ratios or future forecasts? These choices only get more complicated as renewable energy becomes a larger fraction of the electric grid because wind and sunlight are intermittent, requiring energy storage.

PV panels on vegetated roof of Etrium Passive House office building near Cologne. Photo by Greg Duncan

Solar panels on vegetated roof of Etrium Passive House office building near Cologne. Photo: Greg Duncan

Current definitions of Net Zero Energy Buildings—there are at least four—ignore the energy storage and transmission requirements due to renewable energy produced on site. Different uses of energy have different requirements for storage and transmission. Because of these problems, PHI is replacing the primary energy ratio with a new concept, Primary Energy Renewable (PER), that takes into account storage losses as well as production and distribution losses. For example, onsite PV can power air conditioners during summer days when there is plenty of sun, so there is no need for storage and the PER is lower. Conversely, PV systems are not particularly ideal for heating. The PER for heating with electricity—ideally with an air source heat pump instead of direct resistance—is therefore higher. In the future, it will be much more environmentally sound and cost-effective to use renewable energy to cover energy demand for any cooling that may be needed than for heating. These new application-specific PER ratios are also climate specific, dependent on seasonal solar and wind production potential. [Proceedings of the 18thInternational Passive House Conference, pp 648-9. Aachen, Germany 2014. ISBN 978-3-00-045216-1.]

USAF - 070731-F-8831R-001

Utility-scale solar at Nellis Air Force Base USAF – 070731-F-8831R-001

As you can see just from the examples of heating and cooling, calculation of a Net Zero Energy building is complicated. All of them rely on the building itself as the boundary condition for renewable energy production, although sometimes including parking lots and public rights of way. The Net Zero concept discriminates against tall buildings because it is not feasible to install enough PV or wind turbines to meet the energy demands of a 4+ story building. WNYC has an article on the challenges of going solar in an urban environment and why Passive House should be the basis for the design, in order to reduce energy consumption. The article uses the example of a Net Zero Energy school on Staten Island with the luxury of a more suburban location than most of New York City that will open in 2015. This building uses the “trick” of including PV panels over a parking lot.

P.S. 62, being built on Staten Island's South Shore, will have 2,000 solar panels to generate as much energy as the building uses. (Chris Mossa/WNYC)

P.S. 62, being built on Staten Island’s South Shore, will have 2,000 solar panels to generate as much energy as the building uses. (Chris Mossa/WNYC)


To address the discrimination against tall buildings that Net Zero definitions perpetuate, PHI is proposing new classifications based on renewable energy produced on site per lot area rather than floor area:

  • Passive House Classic: unchanged except for the new definition of Primary Energy Renewable. No onsite renewable energy required.
  • Passive House Plus: for a single family house, about as much energy is produced as is consumed.
  • Passive House Premium: for a single family house, produces an energy surplus.

Without changing the Passive House definition, PHI will also start recognizing “Energy Conservation Buildings” that meet a certain threshold for energy efficiency but fall short of meeting the Passive House standard.

Absurdity of Natural Ventilation

I’ve been meaning to post something about the absurdity of the almost religious devotion some people have to “natural” ventilation in a building. How is a double-hung window “natural”, by the way? That’s why I prefer the term manual ventilation.

Fortunately, the Passive House Academy of New Zealand beat me to it with a great Google+ post.

Would you throw your laundry into a river and hope to pick the clothes up cleaned somewhere downstream? Are you doing all your laundry by hand? Do you get fresh air in your car only by opening the windows? Probably not.
Yet, there is this absurd insistence on natural ventilation when it comes to houses – despite research demonstrating poorer outcomes for indoor air quality, comfort and energy efficiency. In many aspects of our daily routines, we accept that a machine can do a better job. What’s different with ventilation of houses? In a mechanically ventilated home, the windows can be opened and closed at will. Freedom of choice! In a manually ventilated home however, the windows cannot be closed without risking the build-up of air contaminants and moisture indoors. The effectiveness of this form of ventilation furthermore depends mainly on the direction and force of wind. In other words: it is relying on the weather. With mechanical ventilation, there is no reliance on power – as in a power outage, occupants can still fall back to manual ventilation. For most of the heating season however, they enjoy great indoor air quality, while saving massively on heating costs, and not having to worry about opening and closing of windows.
Note: ventilation in a Passive House is – deviating from the experience that most of us have with cars or offices – silent, non-draughty, the air is typically not conditioned at all, and sourced filtered directly from the outdoors. Fresh as!

In the past ten years, the efficiency of mechanical ventilation with heat recovery has improved so much that manual ventilation is rarely the most appropriate strategy.

UPDATE: An analysis out of Ireland showed a savings of 643 euros per year for a Passive House with heat recovery ventilation versus natural ventilation.