Window Heat Pumps Promise Cost Savings --- Units are installed like air conditioners and efficiently cool or heat rooms

“A new option for heating and cooling is spreading across the U.S.: window heat pumps.

 

Using heat pumps for climate control isn't new. But, in the past, installation could be costly and complicated -- involving cutting a hole in an exterior wall, as well as ductwork if the heat pump was designed to heat an entire home. Now a new generation of pumps promises similar energy efficiency at a lower cost and easy setup, since they fit into windows much like conventional air conditioners.

 

Although there are some consumer models available, the pumps are largely aimed at potential bulk buyers like housing authorities and landlords, usually those looking to inexpensively upgrade or supplement older heating systems. States, cities, utilities and nonprofits across the country are running pilot programs to see if the pumps deliver on their big promises and identify any flaws.

 

In one large-scale project, the New York City Housing Authority is installing pumps for thousands of tenants in municipal housing.

 

"We were trying to get something moving, especially for older occupied buildings," says Jordan Bonomo, a senior program manager at the housing authority. Some of the old buildings have 80-year-old pipes and radiators. "They don't even make the components anymore," he adds.

 

Proponents hope the rollout will set window heat pumps on a path to wider adoption with cities and landlords -- and eventually individual buyers. The pumps could be effective solutions for "households in multiunit buildings, smaller homes or for folks looking for auxiliary heating/cooling systems in other living spaces," says Lucas Davis, a professor at the University of California Berkeley's Haas School of Business, who has researched heat-pump adoption.

 

There are essentially two categories of window heat pumps: a standard version -- to cool rooms in warm weather and provide some heating in moderate climates or shoulder seasons -- and a more-recent model that generates heat in cold weather, too. The window-mounted version of the cold-weather units came about because of a heat-pump program launched by New York City and state.

 

Five years ago, the Clean Heat for All Challenge called for companies to develop a window-based cold-climate heat pump, with a commitment to buy approximately 30,000 window heat pumps for 10,000 apartments in New York City Housing Authority buildings. (The Clean Heat for All program also offers owners of multifamily residential buildings a $2,250 credit for each window heat pump installed in low- to moderate-income buildings and $1,500 for market-rate buildings.)

 

The housing authority settled on pumps made by two different companies -- Midea and Gradient -- and ran two pilot programs, involving 24 apartment units and 72 heat pumps.

 

The city asked for some technical improvements, but found the window heat pumps reduced the amount of energy needed to heat the apartments by about 84% compared with the original gas boiler, and saved about 56% of the overall heating costs.

 

In part, that is because the original heating system was inefficient: Before, tenants frequently opened windows in winter because the building was so overheated. With the new heat pumps, each apartment can set the temperature individually, and the units don't block the windows the way a typical air-conditioning unit might, since they have a saddle shape that lets the bulky components hang down rather than sit on the sill.

 

Currently, the housing authority plans to install window heat pumps in 20,000 apartments by 2031. Other municipalities, meanwhile, are testing the waters more gradually. Boston's Housing Authority installed 100 window heat pumps in the 50-year-old Hassan Apartment complex, and wants to put window heat pumps in about 200 additional units over the next 12 months.

 

"Window heat pumps are an easy fit with 10% and 15% of Boston Housing Authority buildings," or hundreds of apartments, says Joel Wool, the authority's deputy administrator for sustainability and capital transformation.

 

Just by reducing the reliance on baseboard heating, Hassan Apartments projects to cut its annual electricity consumption by about 12% -- 170,000 kWh -- and prevented the release of 130 metric tons of carbon dioxide.

 

One caveat about the cold-weather pumps is that they need more electricity in frigid environments. When the temperature in New York City dipped into single digits last year, both heat-pump models were able to provide full heat but efficiency dropped, says Bonomo, adding: "They are still more than twice as efficient as a fossil-fuel boiler, even at low temperatures."

 

One organization is testing how the pumps handle the cold in Vermont -- where winter temperatures can drop below zero. The pilot program from Efficiency Vermont, which helps residents make energy-efficient upgrades, involves households living in older homes that aren't very energy efficient. The heat pumps work in tandem with existing heating systems.

 

For now, people who want the pumps have limited options. Midea offers its window heat pumps through distributors for about $3,100.

 

Gradient, which currently sells its units to multifamily buildings, "will start a geographically staged introduction to the residential market in the near future," says Vince Romanin, founder and chief technology officer.

 

Be aware, though: A lot of people might find it tough to do DIY installation of a window-based heat pump. The units weigh about 150 pounds, and it often takes several people to maneuver the unit. Also, individuals must handle potentially tricky tasks like ripping out old heating units and setting up weather stripping.” [1]

 

1. Window Heat Pumps Promise Cost Savings --- Units are installed like air conditioners and efficiently cool or heat rooms. Ward, Lisa.  Wall Street Journal, Eastern edition; New York, N.Y.. 29 Oct 2026: A11.