A clean energy future for this Queens public development is… hanging out the window?

Until two years ago, Maria Lopez, a long­time resi­dent of Woodside Houses public housing complex in Queens, had grown accus­tomed to freezing winters in her fifth-floor apart­ment. Sometimes, her two-bedroom was so cold she resorted to boiling water on the stove to keep warm. ​“I couldn’t sleep, I was so cold, I was shiv­ering,” she said. Meanwhile, other apart­ments at the 20-building devel­op­ment were over­heating. ​“It was never consis­tent, warm apart­ments,” said Tammy Reyes, another resi­dent at Woodside Houses and pres­i­dent of the tenants’ association. 

Then, in 2023, both Lopez and Reyes got to expe­ri­ence heating and cooling through elec­tric heat pumps. The results were transformative.

The Challenge

The climate issues at Woodside Houses are a symptom of a larger problem: Aging, inef­fi­cient, fossil-fuel heating throughout New York City Housing Authority (NYCHA) sites. Woodside Houses has a central gas-fired boiler plant in one building, which sends steam heat to radi­a­tors throughout its 19 other build­ings through a network of pipes — a common central heating system across large apart­ment complexes in New York City. At Woodside Houses, it was also regu­larly the cause of wildly incon­sis­tent temper­a­tures. Then, four years ago during Hurricane Ida, the central boiler room at Woodside Houses was damaged, and the entire campus needed to shift to tempo­rary boilers to generate heating and hot water.

Adding complexity to these issues was NYCHA’s urgent mandate to decar­bonize more than 2,000 aging, steam-heated build­ings to meet emis­sion targets under Local Law 97 (LL97), which applies to resi­den­tial build­ings of more than 25,000 square feet. NYCHA has set a target of cutting carbon emis­sions to meet thresh­olds under LL97 for its entire port­folio of build­ings. This means indi­vidual build­ings have some flex­i­bility, but the agency must still cut emis­sions across all build­ings by 40 percent by 2030 and 80 percent by 2050, rela­tive to a 2005 baseline. 

Such a big infra­struc­tural change was a signif­i­cant under­taking for the 75-year old building complex. For many other large build­ings in the city, the most feasible elec­tri­fi­ca­tion solu­tion has involved installing condensers on the roof connected via refrig­erant lines to mini-split heat pump units in apart­ments. At Woodside, though, this type of infra­struc­ture upgrade would have required cranes, steel supports, holes drilled through walls, and likely an elec­trical capacity upgrade — a costly bundle for an agency that last year oper­ated with a $35 million deficit. ​“With that model, we were not going to meet our goals,” said Jordan Bonomo, senior program manager in NYCHA’s Sustainability Department. A solu­tion was needed that could serve not only Woodside’s imme­diate needs, but also bring its entire port­folio into the future. 

NYCHA had a very partic­ular set of spec­i­fi­ca­tions for its intended heating and cooling upgrade: An afford­able, scal­able heat pump that also worked well in cold climates, could plug into a stan­dard 120V outlet, fit through a double-hung window, deliver effi­cient heating and cooling without refrig­erant lines or rooftop condensers, and be easily installed by on-site main­te­nance staff.

So in 2021, NYCHA launched a compe­ti­tion with $70 million in public funds: The Clean Heat for All Challenge. Partnering with the New York State Energy Research and Development Authority and the New York Power Authority, NYCHA chal­lenged manu­fac­turers to design a new type of heat pump to meet its needs. 

“The capa­bil­i­ties requested had never been done before,” said Erin Upton-Cosulich, chief of staff at Gradient, one of the manu­fac­turers to enter the challenge. 

The Roadmap

Two compa­nies deliv­ered heat pumps that met — and even exceeded — the criteria set by NYCHA. Midea, a Chinese manu­fac­turer, devel­oped a heat pump that can operate at 100 percent heating capacity at 5°F, and performs reli­ably down to ‑13°F. Gradient, a much smaller company based in San Francisco, also deliv­ered a winning heat pump. Upton-Cosulich said it was a ​“massive effort” for the company to apply and win, involving years of working with regu­la­tors and customers to bring the product to life. ​“This was a massive, multi-year, diffi­cult chal­lenge,” she said.

The heat pumps deliv­ered by both compa­nies were compact and quiet, and were easily instal­lable by on-site staff. The biggest hurdle, though, was enhancing cold climate capacity. ​“The single most mean­ingful tech­nical chal­lenge was ensuring our system was powerful enough to keep comfort through the entire cold winter in a city like New York, while still only needing a 120V stan­dard plug,” Upton-Cosulich said.

The Project 

Woodside Houses, still strug­gling with the tempo­rary boilers after the storm damage, was selected by NYCHA as an initial pilot site for the new tech. In 2023, NYCHA installed 72 window heat pump units in 24 apart­ments across two six-story build­ings at the complex. Each two-bedroom apart­ment received three units: One in the living room, and one for each bedroom. NYCHA staff put the units in the windows, and the instal­la­tion took place in just over a week. ​“It was much quicker than a rooftop condenser instal­la­tion with refrig­erant lines — and the equip­ment main­tained consis­tent temper­a­tures in each room,” Bonomo said.

The new equip­ment both heats and cools the apart­ments, so resi­dents with heat pumps have had their steam pipes disabled. They also no longer have tradi­tional air condi­tioning units in their windows. Now, tenants can tweak the heat for their own comfort, even using the cooling feature on the occa­sional hot winter day. ​“It made a big differ­ence for me. Now I am so comfort­able,” Lopez said. 

Both the Gradient and Midea units use a saddle design that rests on the window sill, with the condenser on the outside, and the fan equip­ment on the inside. ​“What I like about it — not just that it works so good — but you can see outside better,” Reyes said. Where the old air condi­tioning units filled the lower window frame, the new all-in-one heat pumps have a much lower profile. 

Many tenants use the top of the unit as a shelf for plants, photos, or other deco­ra­tions. ​“Some people have it fixed up really nice,” Reyes said. Even so, not all tenants were thrilled about test-running the new tech­nology. Some were concerned about conden­sate drip­ping down the exte­rior façade, others about noise. One resi­dent found it was easy for their pet to tamper with the touch screen controls. All this feed­back was trans­ferred to the manu­fac­turers, and Reyes found issues were addressed promptly. 

In spite of initial concerns, resi­dents found the units surpris­ingly quiet. ​“It doesn’t make much noise at all,” Lopez said. The models allow conden­sate to be drained from the inside, limiting external drips. ​“We learned that older customers had a pref­er­ence for phys­ical buttons to touch screens, so we added large buttons for crit­ical func­tion and a remote control,” Upton-Cosulich said. Another concern for tenants was whether the heat pumps would result in a rent increase. NYCHA resi­dents pay a surcharge added to their rent for high-energy elec­tric appli­ances, but the $10 monthly fee normally charged for air condi­tioning units is waived for the heat pumps.

The Future

The new heat pumps have been installed at Woodside Houses for two years, and over that time, sensors have tracked energy perfor­mance. The results indi­cate the heat pumps use around 85 percent less energy compared to the gas-fired steam plant. This increase in effi­ciency trans­lates to a 50 percent cut in utility costs, and a similar reduc­tion in carbon emis­sions. Preliminary results from the oper­a­tion in summer also show compa­rable elec­trical demand to the old air condi­tioner units, despite the fact that there are more heat pumps installed in each apartment.

Although the sample size of 24 apart­ments is very small and it’s unknown whether the study was able to control for the fact of ambient steam heat already in the building, Bonomo says a 50 percent reduc­tion in carbon emis­sions indi­cates that if NYCHA were able to roll the heat pumps across the city’s public housing port­folio by 2030, the agency’s LL97 broader goals would be met. 

Encouraged by the results, NYCHA plans to install 150 Midea heat pumps in a full building at Woodside Houses later this year, and also add triple-pane case­ment windows to increase effi­ciency. ​“This will hope­fully reduce the heat load in the apart­ments, and provide better access to fresh air,” Bonomo said. Increasing the sample size of the pilot will also give more accu­rate infor­ma­tion about energy savings and costs. In the mean­time, a more detailed report with perfor­mance data and find­ings from the current pilot is expected in the coming months. 

As part of the inno­va­tion chal­lenge, NYCHA committed to a bulk purchase of 30,000 units over the next seven years. This brought down the cost of the heat pumps to between $1,700 and $2,260 per unit. Even so, scaling the heat pump tech­nology across NYCHA’s vast port­folio is still a finan­cial chal­lenge. By NYCHA’s own esti­mate, the agency will need roughly 156,000 cold climate window heat pumps over the next decade. ​“We think the cost will come down over time, but the initial heat pump instal­la­tions will be more expen­sive than our busi­ness-as-usual boiler replace­ments,” Bonomo said. NYCHA’s interim plan is to reha­bil­i­tate existing boilers in the port­folio and improve steam distri­b­u­tion. Then, when a boiler replace­ment becomes unavoid­able, if funding can be secured, the building will become a candi­date for the all-in-one heat pumps.

The success at Woodside Houses is already having an impact on deci­sions made by private prop­erty owners. At a six-story prewar co-op in Brooklyn’s Prospect Park South, the board decided to do a small-scale test of Gradient’s all-in-one heat pumps in five apart­ments and monitor the results. ​“The NYCHA pilot gave us confi­dence in the cold weather perfor­mance,” said board member Jackson Lehr. Like Woodside Houses, the 84-unit co-op relies on steam heating and window air condi­tioning. When the board initially looked into decar­bonizing through a central­ized approach, the numbers were eye-watering. ​“It was just millions of dollars and cost prohib­i­tive, so really, the numbers point you to a decen­tral­ized approach,” Lehr said. 

The feed­back on the plug-in heat pumps from their small sample pilot has been unan­i­mously posi­tive, and the co-op is currently plan­ning to move forward with installing the equip­ment in more units throughout the building after further analysis. ​“The ability to have that full control over the temper­a­ture and have a nice even heat is a very pleasant expe­ri­ence for people,” Lehr said. 

The instal­la­tion cost is also about a third of what it would be to put in a new central­ized system. The cost of the Midea all-in-one heat pump for units in the commer­cial market is about $2,800 to $3,000 per unit; Gradient is not disclosing the firm’s commer­cial pricing. ​“It varies based on deploy­ment scale, customer type, and program design,” Upton-Cosulich said. The Prospect Park South co-op plans to pay for the work with reserve funds, plus cash made avail­able from refi­nancing, but they are also looking forward to taking advan­tage of the state and local incen­tives avail­able to them for clean energy upgrades.

Many are hopeful that NYCHA’s strategy could become a model for steam-heated build­ings across the city. ​“The steam-heated sector was facing a tech­no­log­ical barrier, and these window units give them a poten­tial solu­tion,” said Adam Schiabor, asso­ciate director of research at the Urban Green Council. The non-profit expects to see this and other heat pump tech­nolo­gies expand to non-NYCHA build­ings as key for the city to meet its zero-emis­sion goals by 2050: ​“These different vari­a­tions… will allow for more build­ings to take advan­tage of this approach to decarbonization.”