Bringing Passive House Strategies to Affordable Housing

The building’s Passive House elements, which help it substantially lower emissions and surpass NYC Energy Code requirements, include solar shading via deeply recessed windows and projecting fins, a super-insulated building envelope (incorporating foam plastic and woven insulation), high-performance windows, advanced air sealing, energy recovery ventilators (which provide fresh filtered air to apartments and common areas), and space conditioning via all-electric variable refrigerant flow units.

But beyond energy savings, these measures significantly improve air quality, alleviate noise pollution, enhance thermal comfort, and reduce tenants’ energy bills by roughly half, note the architects. While up-front costs are higher, the savings should help the developers gain a return on investment in an estimated 10 to 15 years, says John Woelfling, principal at Dattner Architects.

Woelfling adds that multifamily buildings can multiply Passive House standards’ efficiency via their inherent form factors. “You have more people per square foot than a single-family home, and a lot less exterior envelope,” he says. He sees affordable multifamily housing as a logical partner with Passive House strategies: “I see what we do here at Dattner as a solution to solve or address twin problems of [the] affordable housing crisis and climate crisis.”

The firm has worked on a number of mixed-use, affordable Passive House projects, including 425 Grand Concourse and Santaella Gardens, both in the Bronx. Chestnut Commons’ particular innovation is its community center, which welcomes visitors with a double-height lobby, a central skylight, and bleacher seating. The center was not built to Passive House standards, owing to cost limitations, but rests within the Passive House building’s envelope.

How Chestnut Commons is Building Community

“It’s not just a housing project or community center or teaching kitchen or a bank. It’s got all these rolled into one,” adds associate principal and project manager Keith Engel, who points out that the program also helps activate the building’s exterior, along with its glass-dominated, porous street frontage. He adds that between this building, a new school, and Dattner’s under-construction Atlantic Chestnut affordable mixed-use project (which features 1,200 affordable units, substantial retail, and a rooftop park), the building’s immediate vicinity, which had badly deteriorated, is improving significantly. Chestnut Commons, approved in 2017, was the first to move forward under the East New York Neighborhood Plan, passed in 2016, which focuses on affordable housing preservation and development, economic development, pedestrian-friendly streets, and community resources.

One of the project’s major challenges, adds Woelfling, was the need to closely monitor construction because of the novelty of its Passive House techniques. That meant, for instance, ensuring thermal breaks in the foundation, facade, and roof, to prevent thermal transfer. The project got Phius-certified for overcoming these challenges.

“There were times we had to make sure a very experienced contractor understood this is different than what they’ve been used to doing for the earlier part of their career,” he says. But any extra effort, he adds, has been well worth the payoff on so many levels. “This is a design measure that I think is about equity,” he says. “We should be building these high-quality buildings for everybody.”

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