Passive House Standards Bring Green Living to Affordable Multifamily Housing

Susan Fitter Harris

Green retrofitting is the practice of repairing or rehabilitating a building to include energy-saving or health-promoting features or both. Greening an existing building can make it more energy-efficient, bringing down utility costs for owners and tenants, or it can create a healthier indoor environment for residents, with fewer asthma and allergy triggers such as mold and chemicals.

There is a variety of ways to make a building greener and healthier for its residents, from installing energy-efficient light bulbs to growing fresh food on-site. LISC NYC has helped several community partners achieve greener buildings, and used its experiences to publish a Guide to Green and Healthy Multi-Family Affordable Housing. Given the array of greening choices, some buildings are greener than others. A green building standard known as Passive House, first introduced in Europe in the 1980s, has gained ground in North America in recent years. Designing to Passive House standards can dramatically increase a building’s energy efficiency and reduce its ecological footprint.

What are Passive House design standards?

Passive House standards attempt to leverage climate conditions to reduce energy use while maintaining comfort for residents. To that end, Passive Houses follow these design principles:

  • Continuous insulation throughout the entire building envelope so there is no “thermal bridging,” that is, loss of heat or cool air through gaps in insulation
  • An airtight building envelope to keep outside air out and inside, conditioned air in
  • High-performance windows, typically double- or triple-paned, to use the sun’s energy for heat during the winter and minimize heat loss through the glass
  • A ventilation system with balanced heat and moisture recovery, for
  • A heating and cooling system that is tuned to the size and needs of the space
  • Intentional use of solar gain to maximize use of the sun’s energy but avoid overheating

Some advocates say Passive House standards could create energy savings of 90% over normal construction, but others caution a more modest outlook. Nevertheless, it is clear that Passive Houses result in significant energy savings over housing built to conventional standards. LISC spoke with two affordable housing developers that are leading the way in bringing Passive House standards to affordable multi-family housing.

Passive House apartments grow in Brooklyn

RISEBoro Community Partnership  is a housing and community service organization in the Bushwick section of Brooklyn and is breaking new ground in bringing green building standards to the affordable housing sector. RISEBoro has been developing real estate for 30 years. Its current portfolio comprises 150 buildings and 2,000 units, with an additional 3,000 to 4,000 units in the pipeline.

Ryan Cassidy, Director of Properties for RISEBoro, says that sustainability is a core principle for the organization, and Passive House is the design standard they aim to meet in their projects.  “Our approach in sustainable development is it’s not an add-on or on the fringe. We don’t call it ‘green’ or ‘sustainable.’ We’re talking about building better buildings. Those use less energy, handle ventilation better and get better tenant outcomes.”  RISEBoro is deeply committed to this work; while RISEBoro leadership began by considering the Passive House standard for all of the organization’s new construction, Cassidy says they are now thinking about rehabilitating the existing portfolio to that standard.

As such, energy efficiency and other aspects of sustainability are fundamental to the design of RISEBoro’s new construction or rehab projects. “It goes into everything we talk about. We’re not leaving it on the table to value engineer out.” Cassidy dismisses the concern that green building carries a significant cost premium, noting that RISEBoro has to date built its Passive House projects at the cost of standard buildings. Passive House design “is not tacking on technology to traditional building types,” he says. It starts from the beginning of the design process and requires a different approach to materials and equipment. “A lot of that stuff is low-tech: air sealing, insulation and right-sizing the equipment. We try to keep that really simple. We don’t have a lot of technology in our early building. We just have good thermal envelopes and small systems.”

Part of the reason for green building’s expensive reputation, Cassidy cautions, is that developers assume expensive technological upgrades are needed in order to achieve energy savings. “There is room for improvement in performance because of tech,” he says “but [without it] we are seeing energy loads decrease by 60-80 percent.” In fact, RISEBoro is achieving some of its savings by simplifying the equipment that goes into its buildings. “You need architects and engineers (A&E) to design and size equipment practically,” Cassidy explains. “For example, a giant heating and cooling system [that might go into a standard building of similar size] is not needed for a tight building envelope,” because the heating and cooling system has far less work to do in a Passive House than in a standard building. “The design team needs to be on board. Our work is to find great A&E that get it.”

Finding the right team to work with is key to helping Cassidy mitigate the cost of building Passive Houses. “Some of it just is how the industry works. You have to push back on contractors. Don’t use contractors and architects that upcharge [for sustainable design]. We partner with like-minded people and that helps us execute on the budget, but it is relentless,” he acknowledges. “You have to stay vigilant and clearly identify the cost savings and credits.”

And what of the benefit to RISEBoro’s residents? Cassidy enumerates the advantages of Passive House on several fronts. The tighter building envelope and right-sized systems help maintain a comfortable temperature in the apartments, even if the power goes out. Better insulation allows less noise to travel from outside and between apartments. The air sealing between apartments reduces the spread of smells and pests. Good ventilation and a tight air shield keep cigarette smoke and other pollutants from traveling within the building. With ventilation and air filtering, Cassidy says “we expect much better indoor air quality results and less contaminants like mold, because air is only traveling where you want it to go.” He notes that RISEBoro is currently seeking to study these results on its current project, a rehab of an existing multifamily building to the Passive House standard.

A Passive House for rural seniors

Green building is not just for city dwellers. Lakes Region Community Developers (LRCD) is a housing developer and provider in rural Laconia, New Hampshire (population 16,464) and Rural LISC partner. A few years, LRCD made the strategic decision to integrate sustainability into the organization at every level, from its housing projects to its organizational practices, and received designation as a green organization. LRCD recently completed Gilford Village Knolls III, the third phase of a senior housing development in Gilford, NH, as a Passive House residence. To do so, LRDC’s architect had to revise an existing design to include Passive House features such as triple-glazed windows and continuous insulation.

Gilford Village Knolls III is LRCD’s first Passive House project, but Sal Steven-Hubbard, LRCD Real Estate Development Director, says the organization intends to continue this work. It helps that New Hampshire’s Qualified Allocation Plan for Low Income Housing Tax Credits include points for projects designed to meet Passive House standards. For Steven-Hubbard, it also presented a welcome departure from routine projects. “When we first looked at the project, we thought it would be really simple,” she says. “It was already permitted, designed, etc. But adding Passive House made it a challenge! For me it was really an interesting process.”

Even more interesting will be the ability to see the results of the Passive House design in action. According to Steven-Hubbard, “the Phase II building [standard construction] is basically same design and population and has the same management company, so we will be able to track utility expenses for Phase III next to that building. One of the interesting things we will be able to do is to say what is the difference in what the property is paying for utilities between the different phases.” LRCD is covering all utilities in the Phase III building, anticipating significantly lower energy costs, and Steven-Hubbard is curious to see whether that phase could charge lower rents, since LRCD is not paying utility allowances. LRCD has started benchmarking, but it is too early in the process to see concrete results.

Like Cassidy at RISEBoro, LRCD staff understands the importance of assembling a development team that understands and embraces the intent of a Passive House project. Kara LaSalle, LRCD Real Estate Development Project Manager, notes that the team working on Gilford Village Knolls III was new to Passive House building, but enthusiastic. “The people we worked with were excited to try this and I think it gave them an opportunity to learn a new tool that was applicable to other projects going forward. I thought it was great how excited people were to learn something new in their trade. One of the sheetrockers wanted immediate results every time they did a blower door test!” According to LaSalle, “the biggest takeaway we had was the importance of communications between the design team and the people who are actually implementing what’s going on.” That way, all parties can be assured that the intent of the Passive House design is being carried out in the execution of the project. The builders of Gilford Village Knolls III were committed to getting it right, says Steven-Hubbard. “They tested the air barrier seven times during construction so they could isolate a problem and fix it. By the time it was finished, we knew it was an airtight building.”

While LRCD is optimistic about the energy-saving success of Gilford Village Knolls III and intends to build more Passive Houses, green building does not automatically mean Passive House for this organization. Steven-Hubbard notes, “We are definitely okay with bringing buildings to a higher standard that are less than Passive House. For example, we closed a project yesterday that is a 40-year-old retrofit. It’s expensive as it is and will be enough disruption to the tenants that we didn’t think it justified Passive House.” LRCD has added roof-mounted solar panels to other existing developments and assumed the electric bills for the residents, she says “They’ve seen a reduction in their bills and they are turning out some kilowatts.”

As for the price of green building, LaSalle says LRCD did not find it to be a significant barrier. “We were a little leery upfront about how much more it would cost, but it ended up being 6 percent more to do the Passive House and in the grand scheme of things, that’s not bad at all.” LRDC hopes that 6 percent will be recouped in operating cost savings eventually. “We don’t have a full year of data to see what the savings are monetarily yet,” says LaSalle, “but between that and the planet, I think it’s a win-win.”

“I think if people are thinking about going green, they have to recognize they don’t really have a choice,” says Steven-Hubbard. “As privileged Americans we can choose to ignore the rest of the world, but that’s not who we are as nonprofit developers and that’s not what we want to do. We’ve got to do it!”

Learn more

Check out the following sources for more about Passive House and other sustainable building techniques.

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