Yves here. I welcome reader comments as to how all-in environmentally friendly new construction can be. Nevertheless, a noteworthy feature of this new green complex is that it was built as affordable housing.
By Samantha Maldonado. Originally published at THE CITY on August 13, 2024
It was the midst of a July heat wave, with humidity sticky in the air. Phoebe Saldana sat in the colorful plaza of her East Harlem housing complex, watching her two young daughters ride scooters and climb on workout equipment.
They were getting some playtime outside before returning to the cool respite of their two-bedroom apartment. To Saldana, 37, the air conditioning was a godsend.
“We were living with no air conditioner for a long time,” said Saldana, who moved in from a Brooklyn shelter. “It’s amazing. I, like, never turn it off.”
In the winter, she said, her apartment stays warm, without cold drafts. Inside, she can barely hear the trains chugging along the elevated tracks running next to the building.
“It’s very comfortable to live here. It’s peaceful,” she said.
Saldana lives in Sendero Verde, a 709-unit complex that houses low-income and formerly homeless individuals. Completed in April, it’s the largest certified passive-house building in the United States, and its champions say it can serve as a model as cities and states seek to tackle both the housing crisis and the climate crisis.
“Ideally, this is the way that all affordable housing should be developed,” said Sadie McKeown, president of the Community Preservation Corporation, an affordable housing finance company that was not involved with Sendero Verde. “When you develop something [with] passive house [principles], the benefits to the tenants are great. They get a quieter living environment, they get a healthier living environment and they get lower utility costs… The buildings just stand up better to extreme weather conditions, whether that’s wind, rain, heat or excess cold.”
Developers say Sendero Verde uses about half the energy of a comparable non-passive building thanks to insulation, sealing to prevent leakage, thick windows and ventilation. The result: clean air, quiet interiors, and stable temperatures — even if the power goes out. Spurred by both government incentives and mandates to build greener, such projects offer comfortable, healthy environments to residents often most vulnerable to the effects of a warming planet.
Sendero Verde consists of two mid-rise buildings, completed in 2022, and a 34-story tower, completed in April. Other than the gas water heater, the buildings are powered by electricity, including the stoves in the kitchens. Gas stoves emit methane, a potent greenhouse gas, and have been shown to produce indoor air pollution, contributing to childhood respiratory problems. (Last year, New York became the first state in the nation to ban gas stoves in new buildings, following New York City in 2021.)
There are also community gardens, shared outdoor terraces with native plants, a fitness center, a playground, computer labs and multi-purpose rooms. One of the buildings houses a charter school, with additional space reserved for retail and social services, such as occupational therapy and mental health care.
The goal, said Jonathan Rose, president of Jonathan Rose Companies and one of Sendero Verde’s developers, was to create a “community of opportunity.”
“For our residents, we have a responsibility to give as much resilience as possible,” he said. “So I think passive house is a really good methodology and opportunity for that.”
Sendero Verde, which means “green path” in Spanish, takes up an entire city block in East Harlem, a low-income, formerly redlined neighborhood whose dearth of trees make it significantly hotter than, say, the wealthier, leafier Upper East Side neighborhood a few blocks south.
Those disparities put residents at a higher risk for heat-related illnesses and death. Black and Hispanic New Yorkers are more likely to die from heat stress compared to whites, according to city statistics.
In 2016, as part of a broader neighborhood rezoning plan, the housing authorities called on developers to submit plans for sustainable, affordable housing on a city-owned lot, offering subsidies for the project.
The competition was “a good impetus, kind of getting us and getting others in the industry to maybe speed along this change,” said Jessica Yoon, managing director at L+M Development Partners, one of Sendero Verde’s developers. “We were probably all plodding along towards it anyways.”
Construction costs were about 6% to 8% more than a non-passive house project, according to the developers, though costs have come down since then.
The federal Inflation Reduction Act includes rebates and tax credits that support many elements of passive construction — including for ventilation upgrades and electric appliances — and New York state and city both offer funding and incentives for energy-efficient buildings.
“We’re trying to do dense and smart and land-sensitive buildings, so passive house is a good fit for that naturally,” said Jennifer Bloom Leone, chief sustainability officer for New York City’s Department of Housing Preservation and Development. “As the city moves off of fossil fuels toward all-electric new buildings, passive house can help significantly reduce energy use. This will minimize the risk of grid outages and rising utility costs while providing other benefits like occupant health and safety.”
There are currently over 1,860 certified passive house units in New York, according to data compiled by Passive House Institute U.S., and that figure is soon expected to grow. Last year, state and city officials launched a $15 million fund to “fast-track the creation of 3,000 energy-efficient and all-electric affordable homes in New York City.” The program would support up to 30 buildings — effectively doubling the number of passive projects the city has financed since 2014.
Because they’re so well insulated, passive houses use less energy than traditional homes, which can mean lower utility bills. This efficiency is especially helpful to consumers who are electrifying their homes, since electricity – even though less emissions intensive – often costs more than gas.
“If you’re going to be using electricity as your primary energy source, then you have to be really wise about how you’re using it,” said Laura Humphrey, senior director of energy and sustainability at L+M Development Partners.
Rose, of Jonathan Rose Companies, said given the climate and health benefits of passive housing, all his new construction projects will either be passive or aim to achieve a similar level of energy efficiency.
“We used to have cars without seatbelts, and now we have seatbelts in cars,” he said. “Yes, it costs more, but it saves lives.”
This article is co-published with The Guardian.
There are plenty of examples of passiv or near-passivhaus developments which show it can be done quite efficiently, although there is a limit to how cool you can make an apartment when air temperatures are so high. The general rule of thumb is that it adds between 5 to 20% to capital costs, which is more than enough to justify it economically. The problem, as always with construction, is that the builder is rarely the occupier, so there is rarely an incentive for designers/developers to put the extra design time and money into saving money for the future occupier. Even when people are keen to do it, I’ve seen many occasions when people building their own home end up sacrificing the energy efficiency elements of their new home when they find things going over budget, which of course is the norm in construction.
The big variable is local climate along with land costs and (sometimes) permitted building patterns. Good quality homes designed for very low energy requires careful design and sometimes innovative layouts which can be impractical for any number of reasons.
There are cases where going full passivhaus is not always the most logical. Now that daytime solar electricity is so very cheap in some countries/climates (daytime prices have frequently been negative in Germany this summer), it may be that utilising this energy makes more sense than more insulation or trying to generate power within a site. There are multiple variables involved.
But the technology and knowhow has been available for decades, the only relatively ‘new’ thing with low energy building design is the dramatic reduction in cost of solar and new developments in air exchangers. It all comes down to regulations and the correct incentives.
As to your question Yves, I think one needs to define what environmentally friendly means. A key requirement for this type of building is to be airtight which last I knew could only be achieved with spray foam insulations and even the ones that claim to be green require at least part of their formula to contain petroleum or other fossil fuel derived ingredients.
Additionally, to meet the level of airtightness that is expected most windows don’t open. The buildings require active ventilation and cooling (and dehumidification) at all times. I say required, because they can get uncomfortably warm and more importantly moisture will buildup as it has no passive way to escape. If this goes on for an extended period of time the moisture build up could lead to mold problems (or rot in wood structures). And a knock on here is when the ventilation system does come back online you now could have issues where mold is being pushed into living spaces, at least for some period of time.
I work in a building like this an it’s been nice, but we own the building, the building is generator backed up and we don’t skimp on maintenance.
There are lots of ways to passively cool a building that don’t necessarily require it to be air tight for example modeling it after termite mounds. Also Here are some basic techniques for passive cooling as that is where most of a typical buildings energy demand comes from. If you want to see what can be done with an earth battery and your near Colorado I highly recommend visiting CRIMPI and check out their greenhouse. A friend and I spent an afternoon there harvesting hundreds of tomatoes off the largest plant I’ve seen and then hacking it back because it had grown too large and was shading out a large section of the greenhouse. A problem I could only wish for.
I have participated and seen results on renovating century plus victorian houses (in USA). Sealing them airtight is a disaster, even with air to air heat and humidity exchangers. However, huge achievements in HVAC can be achieved if you work with the building.
The most successful one i helped on was a 170 year old house in PA. Ground source heat pump was key, and we got it to drive the old radiators, and put in hydronic in some areas. New double pane windows were next and wise application of caulk and weather strip was third. Yes, air to air heat and humidity exchange was involved, but we never sealed it tight, need ventilation in those old timbers.
The worst i ever saw, thankfully not involved in, was an incompetent job, where they discovered after some destructive experimentation that lath and plaster walls (with horsehair in the plaster) could not be spray foamed. To compensate i suppose the injected it everywhere else they could. Mold problems after two weeks, more disaster followed. A friend of mine eventually bought it, ripped it all down to the outside brick, (lath and plaster horsehair mostly was unrecoverable after damp and mold), tuck pointed the whole thing, which they should have done in the beginning, managed to save some of the old timber structure (treetrunks for joists in the basement with century plus old bark still on them), wainscotting, doors, baseboards and the like and will probably take him another half decade to finish.
If you build from scratch, passivhaus is a great idea. Refitting old structures is much more difficult.
sidd