When Sendero Verde, a 100-percent affordable apartment development in East Harlem in New York City, opens its doors in 2022, it’ll live up to its name, which means Green Path in Spanish. Within the city block where the new series of high-rise towers will stand, residents of the 361 apartments will be able to stroll through new landscaping and public spaces. A charter school will be on-site and a short walk away.
The development will also exemplify a green path in a more symbolic sense: Sendero Verde will be the largest passive house apartment building in the nation, exemplifying environmentally sound construction practices.
Building designed and constructed to the passive house standard have a number of sustainability goals in mind—including a tightly sealed exterior, sustainable energy use, and improved air quality—making them both efficient and extremely cheap and sustainable to heat and cool. And this style, once reserved for expensive single-family homes, is becoming increasingly popular for new multi-family projects.
Sendero Verde is far from the only large-scale passive house apartment project in the works. In Kansas City, the under-construction Second and Delaware Project will add 276 luxury rental units to the Market City neighborhood when it opens this fall. And in Cambridge, Massachusetts, the under-construction Finch Cambridge passive house project will be the largest affordable housing project completed in the city in at least the last four decades.
This building style offers a significant benefit to tenants, especially those living in affordable housing. Residents of a passive house building enjoy lower utility bills and better air quality. The nation’s underfunded affordable housing stock—which loses 10,000 units annually due to deterioration and lack of maintenance—will need to be replaced and expanded in the coming years. Such an investment was a key plank in the housing platforms of many Democratic presidential hopefuls this year, including the People’s Housing Platform of representatives Alexandria Ocasio-Cortez and Ilhan Omar, which would set aside billions of dollars for clean energy retrofits.
Apartments that cut emissions and have clearer air
Passive house projects utilize a few main design features to achieve such exemplary energy efficiency and clean air. The building envelopes, or exterior walls, of passive house projects are extremely tight and feature triple-paned windows and continuous insulation, leading to exceptional heat retention; heating bills are slashed in the winter, and cooling in the summer is cheaper because hot air is kept out.
But, due to that very tight building envelope, each project also requires advanced heating, ventilation, and air conditioning (HVAC) systems to move air into and around the building, otherwise it would quickly grow stale.
The need for mechanical air circulation results in dramatically better indoor air quality, a huge benefit according to Spencer Orkus, a developer for one of the firms working on the Sendero Verde project in East Harlem.
“Many parts of New York City, such as the Bronx, have some of the highest concentrations of asthma in the world,” says Orkus. “Car exhaust is a huge contributor. In a passive house building with constantly filtered air and controlled temperatures, where you don’t need to open windows to keep cool, there will be extensive benefits for residents who may have been prone to lung damage.”
Those lower heating and cooling costs filter down to tenants, and can be a big financial boon for lower-income renters. Orkus’s firm, L+M Development Partners, also helped open a project called Beach Green Dunes II, in the coastal Far Rockaway neighborhood of New York City. This 127-unit passive house project included a geothermal heating and cooling system that, combined with the building’s energy efficiency, significantly cut utility costs for tenants. Traditionally in older New York apartments, landlords pay heating costs, especially in older buildings using steam-pipe systems run by oil-burning boilers, while tenants pay for cooling and air conditioning, often in the form of window units that can be big energy hogs. Orkus says Beach Green tenants paid roughly $10 a month max for cooling costs during the summer months; in some places in New York, those bills can be $100 or more a month.
“This technology really makes it more affordable for many tenants,” he says. “Someone on limited income, such as a senior, can comfortably cool their apartment at an affordable price.”
Orkus says that large-scale passive house projects can offer incredible energy savings for buildings owners, approaching 75 to 80 percent in some cases. Even more benefits are possible with fully electrified projects, built without any gas appliances or heating, that rely solely on electric heat pumps. Since heating with electricity can be more expensive than using natural gas, the only way to both get rid of fossil fuels in residential settings while keeping a lid on costs, Orkus says, is to build super energy-efficient buildings.
The developers and architects interviewed for this story say that passive house constructions adds around 5 percent to the initial cost of a building, and doesn’t require a longer construction cycle. This means that landlords, especially institutional owners such as housing authorities or school districts, can reap financial benefits over time due to lower operating costs and utility bills, with a relatively small upfront investment.
That’s the theory that AJ Pires, president of Brooklyn-based Alloy Development, is testing out with the firm’s new project for the New York City Department of Education. The firm is developing a campus for downtown Brooklyn that will include a yet-unnamed elementary school and a new home for the Khalil Gibran High School designed by Architecture Research Office. Both will start construction this spring and open in the fall of 2023, and both will be built to passive-house standards.
“This is a great opportunity to push the school construction authority to adopt new ideas to reduce their total energy use,” says Pires. “This can impact the lives of a lot of people over the next few decades.”
Another forthcoming passive house project in New York is the The Lirio Building—a 112-unit project by the Hudson Companies and Housing Works that will bring new affordable housing to Manhattan’s Hell’s Kitchen—which exemplifies the benefits of swapping out the old with the new, according to architect Brian McFarland of CetraRuddy.
“There’s a lot of aging tenement building stock where the air isn’t really being circulated,” McFarland says. “I do think this makes a difference in terms of affordable housing investment. I think our developer client sees the long-term return on it.”
A greener future with passive house buildings
As passive house construction becomes more widespread in multifamily and affordable-housing projects, it can make public investment in housing go further over time. Not every region or climate is a great fit for this type of construction, such as tropical Southern Florida, but for much of the northern half of the United States, it can offer big advantages.
Building to the passive house standard also gets ahead of the increasingly strict building codes being passed by cities and states in the name of sustainability. In New York City, the city’s new energy code passed in 2019 “basically requires buildings to be about 80 percent of the way” to passive house, says Orkus. And last year’s Local Law 97 places a cap on building emissions, which will make more developers look towards any technology that can cut heating and cooling costs over time.
In a warming world, it only makes sense to do what’s possible to cut the carbon emissions connected to buildings. Designing and developing buildings that are more energy efficient makes it easier to breathe in more ways than one.
“These buildings are so insulated and efficient, you’ll be air conditioning more than heating,” says Orkus. “I’ve heard some owners say they never need to turn on the heating.”