If the global energy crisis has got you down, a heat pump might help

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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 like 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 last 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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Q: 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 travelling 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).

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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).

Q: Why are heat pumps more energy efficient?

A: 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.

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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.”

Q: What are the different types of heat pumps?

A: Air-to-air heat pumps: By far the most popular kind of heat pumps, these source heat from the air outside and bring it inside. They move air through the home via ducts, just as a central heating and cooling system does. If you already have a home with air ducts, this is likely the best fit for you.

Mini-splits: They use the same air-to-air technology, but they don’t require ducts. Just as air-to-air heat pumps are similar to a central heating and cooling system, mini-splits are the equivalent of adding a window-unit air-conditioner to a room. They can be a great option for an addition, when you don’t want to extend the ducts from your original home to the new structure. You might also consider them if you want to separately control the temperatures in different parts of your house.

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Geothermal heat pumps: These are by far the most expensive option to install. Geothermal pumps move heat from deep within the earth, through underground pipes and into your home. (Some versions get heat from water sources, but otherwise function the same way.) Installing one is a major construction project, and you can’t easily alter it once it’s in.

Q: Should I get a heat pump?

A: 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, like 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 per cent 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.”

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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. So, 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,” says Taylor. “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.

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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 Farenehit, 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.

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Installing a heat pump in your home will most likely 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 US$7,000 and US$15,000 on average. Depending 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 US$8,000 in rebates for purchasing a heat pump starting in 2023.

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