Our team has recently been engaged as the exclusive marketing agent to represent the developers in the sale of the condos at the first multi-family Passive House to be built in the United States. For some of our potential customers, and perhaps those in the real estate community, this raises the question: “So what is a Passive House?” We thought we would take a look at the basics.
According the Passive House Institute U.S.:
“A Passive House is a very well-insulated, virtually air-tight building that is primarily heated by passive solar gain and by internal gains from people, electrical equipment, etc. Energy losses are minimized. Any remaining heat demand is provided by an extremely small source. Avoidance of heat gain through shading and window orientation also helps to limit any cooling load, which is similarly minimized. An energy recovery ventilator provides a constant, balanced fresh air supply. The result is an impressive system that not only saves up to 90% of space heating costs, but also provides a uniquely terrific indoor air quality.”
The PassivHaus standard arose out of a collaboration that begin in 1988 between Professor Bo Adamson of Lund University in Sweden and Professor Wolfgang Feist of the Institute for Housing and Environment in Germany. The collaboration ultimately grew into the development of a standard that could be applied methodologically to any property type. Today, there are more than 25,000 Passive Houses in Europe and dozens of certified buildings in the United States with hundreds more now being planned across the country.
Unlike other sustainable development standards, Passive House certification focuses primarily on reducing the energy consumption of the building by reducing the heating and cooling demand to a level near zero. Over the course of a building’s lifespan, 85% of its environmental impact is caused by energy consumption. To reduce that impact, Passive Houses focus on the quality of the building’s envelope and the orientation and design of the structure. The envelope’s thermal performance must be optimal, it must be virtually air-tight and free of heat-bridges (see the Thermogram below. The dark colors show how little heat is escaping from the Passive House on the right and how much is escaping from the traditionally built building on the left).
In order to receive certification as a Passive House, a building must meet the following absolute requirements:
- It must have an annual heating demand of not more than 15kWh/m² per year (4746 btu/ft² per year) in heating and 15 kWh/m² per year cooling energy OR be designed with a peak heat load of 10W/m²
- Total primary energy (source energy for electricity and etc.) consumption (primary energy for heating, hot water and electricity) must not be more than 120 kWh/m² per year (3.79 × 104 btu/ft² per year)
- The building must not leak more air than 0.6 times the house volume per hour (n50 ≤ 0.6 / hour) at 50 Pa (N/m²) as tested by a blower door
There appears to be quite an interest in Passive Houses in the United States. Our team has been networking at sustainable development events in recent months and have met a myriad of architects, engineers, contractors, developers, and end users with an interest in building to the standard. There are numerous other single family homes that have been built as Passive Houses in Brooklyn and we recently heard of two planned condominium developments totaling more than thirty units. Last year, when the Passive House in the Woods opened its doors to visitors, more than 2,000 people came to learn about the property in a six week period.
If you are interested in learning more about the Passive House standard, there are literally thousands of great resources available with a quick Google search (don’t forget to check out all the great videos on You Tube as well). If you are interested in speaking to our team about developing, purchasing, or selling a Passive House building, please feel free to reach out to us at (212) 400-4838 or via e-mail at mike@AHBrooklyn.com