Concentration of CO2 in the Atmosphere

Can a Passive House be Beautiful, Functional, and Organic?

An Interview with Hank Keating

 Stone Fruit Farm in Westport, MA.

Stone Fruit Farm in Westport, MA.

By Barbara Whitchurch

Stone Fruit Farm, completed in 2016, is a complex of buildings in the small town of Westport, Massachusetts, built to the Passive House (PH) standard. It calls to mind the design of the classic New England connected farmhouse (main house, connected to out-buildings, plus a barn). The main house includes a master bedroom with a study and a two-bedroom guest area. Because it was designed to serve as an organic farming operation, it also includes a one-bedroom apartment for a farm intern. In addition, there are six totally passive (no heating or cooling) outbuildings, including garage, workshop, barn, greenhouse, root cellar and their connecting corridor. Solar domestic hot water and a 7.6 kW photovoltaic array were sized to be net-positive for the habitable structures.

Green Energy Times was fortunate to be able to interview the owner-architect, Hank Keating, to get a sense of the development of this project. Hank recently retired from his position with a large development company, but continues to consult on large-scale affordable housing projects including a 28 story passive house high-rise in New York City.

The living room

The living room

GET: Tell me about the history of this project.

Keating: Over the last many years, my wife and I had a vision of creating an experimental organic farm. We were living in Boston when we bought the land 10 years ago and started designing the house. My wife runs it as an “incubator farm” where people can test their ideas. We now rent the apartment to a young couple that includes access to the land, the equipment and the apartment in exchange for labor on the property. I hired Mike Katon of the Valle Group to manage the construction, but I remained very involved in the project.

GET: What about the unusual configuration of the buildings?

Keating: An unconditioned passive corridor connects all of the outbuildings and the guest area of the main house. Temperatures on sunny days range from 25 to 125 degrees. We used concrete blocks with dark aggregate, which absorb heat during the day and radiate it into the outbuildings at night. Insulation between buildings prevents loss of heat to the outside. We run our clothesline down the corridor to dry our laundry.

GET: Can you give us some of the numbers for the techies among us?

Keating: Sure. Passive House is currently the highest energy performance/comfort/health standard of construction. While there are energy modeling tools that can be used for any kind of building, a Passive House building has special tools designed just for it (PHPP and WUFI Passive). The certified PHPP modeler for this project was Mike Duclos, whom I had the good fortune to meet at a Passive House conference.

The building’s estimated primary energy demand (energy per square meter) is 105 kWh/m2/yr. Blower door: .46ACH50. Total net positive to date: 3471 kWh (as of Dec. 2016). Insulation: loose fiberglass, dense-packed; R-value in walls R71; roof R100. Windows: Tilt-turn Yaro triple-pane, with U-value of U.15 and SHGC U.62.

The house uses Mitsubishi air-source heat pump mini-splits and a Novus 300 HRV from Zehnder for heating/ventilation. In addition, there are two ethanol alcohol fireplaces. They aren’t ducted, but the HRV in “boost” mode compensates for any oxygen burned and CO2 discharged.

Interior view of solar corridor. All photos: Jon Moore Photography

Interior view of solar corridor. All photos: Jon Moore Photography

GET: Any tips for future builders or designers?

Keating: I’d recommend that all builders take the Passive House Builder’s Training. And the full team, including primary subs, architect, and PH consultant, should have regular meetings focusing only on PH issues. It’s crucial for everyone to work together in a coordinated way when building a high performance home, because attention to detail is critically important.

GET: How do you like living in a Passive House?

Keating: We love it! Its most unique feature is that all rooms have southern exposure. I call it a “single story candy bar,” 19 feet wide by 85 feet long. Every space gets direct sunlight and direct heating from the sun. The comfort level is fantastic. We have never actually turned the heat on! One night, a year ago, it was six below, the inside temp went down to 61. When the sun came out, it was back to 72. Because there are no drafts, we find temperatures of mid-60’s to mid-70’s totally comfortable. My wife, who is a gardener-farmer who always wants to be out in the dirt, says she feels “like I’m outside already” because of the views and sunlight from the large southern windows.

Stone Fruit Farm is featured in Green Builder Magazine () and in Passive House Buildings: New England Forges Ahead ().

Barbara Whitchurch is a member of the Outreach Committee at Passive House VT.

Many thanks to our sponsor:

Valle Group Logo_April 2017

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