For now, the window heat pump in apartment 1D sticks out like a sore thumb. Set between off-white lace curtains, it looks like a brand-new oven installed in a grandma’s living room. 

The heat pump replaced a radiator — those rattling, hissing things that are hallmarks of most old buildings in New York City. And if the heat pump proves itself this winter, it could one day make its way into virtually every room in every home in the city’s public housing system. And that could just be the start for the future of home heating. 

The prototype in this room at the Woodside Houses in Queens, New York, is already an engineering feat that New York state has funneled tens of millions of dollars into developing because nothing like it was on the market. Heat pumps can both heat and cool a home. To be sure, more complicated versions of the appliance have been around for a while. This one is novel because it’s simple. It can sit on a sill and plug into a wall like a window AC unit.

So far, the state has purchased 30,000 of them for New York City’s public housing as part of its plan to tackle climate change. They’re supposed to save energy, cut down utility costs, reduce pollution, and give residents access to air conditioning that didn’t have it before. 

But some public housing residents are already tired of the New York City Housing Authority’s promises to make upgrades only to botch plans or backtrack later. “Don’t use a human being for experiments, tell them that,” says Alexa Cruz, who has lived in a public housing development in Manhattan since 1969.

This is, in fact, a huge testing ground for an appliance on which many other governments are pinning their climate ambitions. The Biden administration invoked the Defense Production Act last year to supercharge domestic manufacturing of heat pumps. The European Union has a goal of deploying 10 million heat pumps over five years. And yet, one big barrier to adoption has been the lack of a viable version of this technology for renters. 

That’s something New York will see if it can change, starting with public housing first. Ultimately, it’s not just the technology that’s being put to the test but also the ability of state and local officials to center the residents who have been the most marginalized in the past. Whether it passes those tests could have repercussions for other renters also.  

Just 10 percent of households worldwide have heat pumps today. Those are typically bigger, more complex, and expensive systems that need to be professionally installed. For those reasons, they’re usually out of reach for renters. NYCHA actually did a test run with one of those existing options, called a split system unit, which involved mounting equipment on the roof and on the wall in a tenant’s home. It ended up being too unwieldy, and the project stopped there. 

Unfortunately, when it comes to new, more efficient appliances and clean energy technologies, it’s typically more affluent households that can afford to bring these new things into their homes first. The benefits don’t usually trickle down to lower-income households until later, if at all. 

New York is attempting to flip that scenario now by purchasing new window heat pumps for public housing residents. “The beauty of this project is that some of the lowest-income residents in the city are experiencing the newest technology for the first time so they’re leading in this area, which is really nice and something that we’re very proud of,” says Justin Driscoll, president and CEO of New York Power Authority, the public power organization that procures electricity for NYCHA.

The big motivation to switch to heat pumps now, though, is a deadline. Back in 2019, New York state passed a law to reduce the greenhouse gas emissions causing climate change by 85 percent by 2050. That was pretty progressive environmental legislation at the time. Now, more than 90 countries have made commitments to reach net-zero greenhouse gas emissions by roughly the same date. It’s a target climate scientists have found could save millions of lives from worsening climate-related disasters like floods and extreme heat.

Heat and hot water in buildings create about 40 percent of New York City’s planet-heating greenhouse gas emissions. So, in 2021, NYCHA and its partners announced a $263 million investment in electric heat pumps. They called it the “Clean Heat for All Challenge,” a competition for companies to design a heat pump that would work in cold climates and be installed in existing windows. 

Electric heat pumps are considered more environmentally friendly because they can run on wind and solar energy instead of fossil fuels. They’re also more efficient because they don’t actually need to generate heat like other systems do. Instead, they just move heat around to where it’s needed most.

In the traditional heating system of a public housing development, gas-fired boilers generate hot steam that then gets piped up through apartments. A heat pump, in contrast, uses a refrigerant to draw in heat from the outside air. This works even in the wintertime as long as the refrigerant is colder than its surroundings. Thanks to advances in heat pump designs over the past decade, they can now heat homes even when outdoor temperatures reach subzero. 

To cool a home in the summertime, the system works in reverse to essentially pump hot air out of the building. (There are different kinds of heat pumps. For this story, we’re focusing on the most common kind, called an air source heat pump. The Verge has an explainer here.) 

But the technology had yet to shrink down to window size, in part because these kinds of appliances generally get more efficient the bigger they are. 

Two companies ultimately won the Clean Heat for All Challenge last year: appliance manufacturer Midea and San Francisco startup Gradient. New York Power Authority shelled out the initial $70 million in financing for the first 30,000 heat pumps. The New York State Energy Research and Development Authority put in another $13 million for the demonstration phase of the project.

They won’t install all 30,000 units at once — which is still only enough for around 10 percent of public housing in the city. Last summer, NYCHA placed 36 units from Midea with tenants in a housing development in Queens. Another 36 are supposed to be installed in residents’ homes by the end of the year. They’ll monitor those units throughout the winter, measuring how much energy they use and checking indoor temperatures. 

“If these prove successful over this winter heating season and we’re satisfied, and the residents are satisfied, and our operation staff is satisfied, and everybody’s happy” then the “ideal scenario is that we would be basically installing these in every apartment, bedroom, living room,” says Jordan Bonomo, senior project manager at NYCHA. “That would be the new heat.” 

Over the next five to 10 years, NYCHA thinks it might need 156,000 window heat pumps to comply with local climate law. 

Residents are understandably nervous. “I’m an elderly woman and I want to make sure they’re not going to kill me,” says Cruz, the NYCHA tenant. “I don’t want to be used as an experiment.” 

She has a lot of questions for NYCHA about the heat pumps: Is it safe? How much is it going to cost to install and run? What about maintenance? Cruz hadn’t heard about the heat pump initiative until The Verge reached out to a tenant advocacy group called Fight for NYCHA. Members of the group are worried about whether a switch to heat pumps might wind up shifting costs to tenants.

NYCHA currently pays for residents’ heating and electricity in a majority of its buildings, which the agency says wouldn’t change. It also tells The Verge it would take care of the costs of installing any new heat pumps. But it hasn’t made any decisions yet on air conditioning costs. At the moment, NYCHA residents have to buy their own window AC unit and pay a monthly fee to use it. 

Air conditioning has been a challenge for the city. It’s becoming more of a necessity than a luxury with climate change. Heatwaves are becoming more extreme, killing more people in the US than any other weather-related disaster.

But AC units can also be too expensive for many residents to install and operate. The Bill de Blasio administration tried giving out thousands of free air conditioners to senior citizens in low-income housing during the covid-19 pandemic in 2020. Fast-forward to this year, and NYCHA has asked residents to give up their AC units, pay the monthly fees, or face eviction, Politico reported. It’s just one example of the city saying they’ll provide a free resource to NYCHA residents only to ask them to pay for it later, residents tell The Verge.

Vera Naseva got one of those AC units from NYCHA. It’s not the best window AC unit she’s had over the years, she says. It’s noisy. And the way it’s installed lets in water through the window during storms. But now, it’s the only AC she has. And she says NYCHA is going to take it back soon. After that experience, she has major concerns about how well the new heat pumps will perform, especially in the cold. “I’m not happy, it really scares me,” she tells The Verge.

The Verge wasn’t able to get in touch with NYCHA residents who already have a new heat pump installed. NYCHA offered a site visit to one of its buildings in Queens to see the prototype in 1D, a former residential unit being converted into a resident association office. There, we spoke with NYCHA staff and a couple members of the tenant association. 

Tammy Reyes, a resident and the association’s treasurer says she’s happy that the new heat pump doesn’t block the window like a typical AC unit would since it hangs down from the sill. And there’s no need to worry about kids burning themselves on the radiator, says the tenant association president, Nan McKie. 

But, she asks during the site visit, what happens if a kid squirts liquid into the vent? She has a one-year-old granddaughter with a habit of squeezing juice out of her Capri Sun straw. The questions start to snowball. Will residents face charges for any damage to the heat pump? Will work orders be expedited? And how many extra units will NYCHA keep on hand for any necessary replacements?

NYCHA is still figuring out the answers to all of these questions. For now, the residents with the first batch of heat pumps have Bonomo’s cellphone number to call if anything pops up. They’ve had to fix insulation around one unit to stop rain leaking in from the outside, for instance. Overall, NYCHA says things are going smoothly. 

The real test will come this winter. NYCHA selected the homes of residents that would be easiest to isolate from the building’s boiler to install the first set of heat pumps. They’ll rely entirely on the new units to stay warm. Heat pumps have to work harder in the winter than the summer because that’s when the gap between temperatures outside and what’s comfortable inside is the greatest. 

The agency has been under federal monitor since 2019 after an investigation into years of mismanagement and unsafe housing conditions, including heat outages that affected hundreds of thousands of residents. A 2020 audit from the New York City comptroller found that NYCHA “failed to maintain a complete inventory of its boilers, adequate records that boiler inspections were conducted, and to ensure that deficiencies cited in inspections were corrected.” Under the terms of the monitorship, NYCHA is supposed to replace aging boilers.

NYCHA thinks replacing those boilers with individual heat pumps could avoid a dangerous loss of heating across an entire building. If a boiler goes out, a whole building might lose heat. But if one heat pump goes out in someone’s living room, for instance, that shouldn’t affect another heat pump in the bedroom. Even so, it’s not just the technology that’s under scrutiny — it’s NYCHA’s ability to manage it. It’s a microcosm of how cities and power grids could have a steep learning curve ahead as they try to implement potential climate solutions. And it shows what’s at stake if they don’t pay attention to the residents most affected by the changes. 

The heat pump design in 1D doesn’t have an official name yet. It was designed by Midea, which hopes to make it publicly available by 2024. Gradient’s website says it’ll be accepting preorders soon for its All-Weather 120V, the same kind of unit it’s offering to NYCHA. An older version of its heat pump, which wasn’t designed to work in temperatures as cold as the new unit can operate in, retails for close to $5,000. That’s a hefty price tag for a renter if you’re comparing it to a window AC unit, and the new unit isn’t likely to be cheaper. 

But Gradient’s new unit was designed to be powerful enough to replace a radiator, and a heat pump is more cost-competitive when it’s simultaneously replacing traditional heating and air conditioning systems. Moreover, the biggest impact heat pumps can make won’t come from enticing individual consumers — replacing appliances one apartment at a time. It comes from making gas boilers obsolete for entire buildings. The way to make more energy-efficient appliances accessible to renters might also be to make sure they’re already in the building. 

NYCHA is the biggest landlord in New York City, after all, and is already thinking about the possibility of putting this new technology in many of its more than 177,000 apartments. New York Power Authority says it’s also considering installing heat pumps across other governmental properties it serves. Those kinds of contracts have the power to make heat pumps the new norm by giving the industry incentive to scale and lowering manufacturing costs. 

That kind of shift will come with new challenges, of course, and other things will have to change to avoid passing on costs to renters. In New York City, for example, landlords are required to provide heat and often take care of gas bills, while it’s common for tenants to pay for electricity. Without the right policies in place, an electric heat pump could shift heating costs to renters’ tabs. That probably wouldn’t go over well with renters, so policymakers and building managers will need to listen to them, too, if they’re hoping for a smooth and just transition. 

“You have to take a kind of a wider approach to how you electrify the building,” says Gradient CEO Vince Romanin. “We saw this coming. I don’t think we saw how fast this was coming.”