What is a heat pump, and how does it work?

Despite their name, heat pumps can both heat and cool a space. They work by transferring heat rather than creating it. In cold weather, they pump heat from outside your home to the inside to warm your interior. An outdoor unit extracts warm air, then sends it traveling through a refrigerant line connected to an indoor unit. The air gets compressed along the way, which heats it up even more before it gets pushed into the home. In warm weather, the system does the reverse: sucking up warm air from inside and pumping it outdoors (which is also how a typical air conditioner works). Of course, this all raises an obvious question: In the winter, where does the heat pump find warmth outside to bring indoors? As it turns out, even when it’s tremendously chilly, there’s still thermal energy in the air and ground. (Heat energy is present as long as the temperature remains above absolute zero.) Heat likes to move from warmer objects to cooler ones, so the refrigerant attracts the heat to the pumping system. Still, just like other heating systems, heat pumps have to work harder when it’s very cold, which will be reflected in the amount of energy used (and in your electricity bills).

Why are heat pumps more energy efficient?

Heat pumps are more energy efficient than fossil-fuel-reliant furnaces and air conditioners because they run solely on electricity. And they don’t actually generate heat — remember, they just move it from one location to another — so they use less energy than other electric-powered heating and cooling systems, too. Because heat pumps use the same equipment to both heat and cool a space, they’re also “more convenient in terms of maintenance and handling,” says Yusuff Yusuff, the service manager at Mitchell Heating and Cooling in D.C. “You don’t have to worry about so many parts.”

Should I get a heat pump?

There are a number of factors to consider when deciding whether to replace another type of heating and cooling system with a heat pump. First, you’ll want to think about the climate in which you live. Though heat pumps tend to do best in moderate environments, such as the Mid-Atlantic, they can also work well in places with harsh winters. Take Norway, a country not exactly known for its year-round warmth: 60 percent of buildings there have heat pumps . The country opted to subsidize heat pump adoption on a wide scale after the oil crises in the 1970s, says Michael Taylor, a senior analyst at the International Renewable Energy Agency. The effort was helped by technology improvements that now allow heat pumps to operate “very efficiently at very low temperatures.” One thing to keep in mind about heat pumps is that they work best in concert with other measures to improve your home’s energy efficiency , such as the insulation in your walls and around your windows and doors . If you have old, drafty windows, a heat pump isn’t going to immediately turn your home into a cozy haven from the cold. To get the most out of it, you’ll probably need to upgrade your windows as well. “It’s so much better to do a heat pump installation when you have time to consider the building holistically,” Taylor says. “If your furnace dies, it’s a bad time to go shopping for a heat pump,” he explains, because you’ll want to be able to fully assess your energy needs, rather than make a snap judgment during an emergency. Others opt for more of a hybrid approach. Bill Royston, owner of D.C.-area HVAC company All-Pro Services, recommends keeping an auxiliary heating source if you live in a place where temperatures consistently drop below freezing. One option is to add electric heat strips to a heat pump’s indoor unit, which turn on for additional warmth as backup in especially cold weather. Another strategy is to do what Royston does at his own home in Deale, Md.: In addition to his heat pump, he also has a propane furnace. For the most part, he relies solely on the heat pump, but when the temperature dips below 40 degrees, he’ll have the furnace kick in as well. Even so, he says, his energy costs are much lower than they’d be without the heat pump, because the furnace has to do significantly less work. Installing a heat pump in your home will probably slash your energy costs, too, but you’ll also have to weigh the upfront investment of putting one in. Installing an air-to-air heat pump can cost between $7,000 and $15,000 on average. Depending on where you live, there may be rebates and incentives available to help defray the cost. The best place to look for those is through your local utility company. At the national level, the Inflation Reduction Act will offer up to $8,000 in rebates for purchasing a heat pump starting in 2023.

The Home You Own

What is a heat pump, and should I get one?

Here’s a primer on the increasingly popular energy-efficient alternative to your fossil-fuel-powered furnace

By Rachel Kurzius

December 13, 2022 at 6:00 a.m. EST

Photo illustration of a heat pump isolated on a light beige background, with orange and yellow heat squiggles to the left and blue cool air squiggles to the right — (iStock/Chloe Meister/Washington Post illustration)

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7 min

If you’ve been hearing a lot about heat pumps but you still don’t really understand what one is, you’re not alone. In places such as Sweden and Switzerland, they’ve long been a common option for controlling the temperature of homes. But heat pumps have only recently gained traction in the United States thanks to a global energy crisis and rising awareness that the all-electric systems are more efficient than typical furnaces and air conditioners. Their profile also got a boost in the summer with the passage of the Inflation Reduction Act, which includes incentives for adopting them.

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Advances in technology have made heat pumps more effective in colder climates, and with energy costs expected to keep rising, more American homeowners are now considering installing them as a possible way to reduce their utility bills. Whether a heat pump makes sense for your home will depend on several variables. Here’s a primer.

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