A Heat Pump Might Be Right for Your Home. Here’s Everything to Know.

“A heat pump is probably the biggest thing that consumers can do to help fight the climate crisis,” said Amy Boyd, director of policy for the Acadia Center, a regional research and advocacy organization focusing on clean-energy policy in the Northeast. Heat pumps also happen to rank among the quietest and most comfortable options available for home heating and cooling.

Heat pumps are essentially two-way air conditioners. In the summertime, they work like any other AC unit, removing heat from the air inside and pushing cooled air back into the room. In the cooler months, they do the opposite, drawing heat energy from the air outside and moving it into your home to warm things up. The process is especially efficient, typically using one-third of the energy (and sometimes even less!) than other home-heating sources. Or, as David Yuill of the University of Nebraska–Lincoln told us, “You could put in a watt of electricity and get [the equivalent of] four watts of heat out of it. It’s like magic.”

Unlike magic, however, there’s actually a very simple explanation for this result: Heat pumps have only to move heat, instead of generating it by combusting a fuel source. Even the most efficient gas-powered furnace or boiler never converts 100% of its fuel into heat; it’s always going to lose something in the conversion process. A good electric-resistance heater gives you 100% efficiency, but it still has to burn watts to produce that heat, whereas a heat pump just moves the heat. More than 92 percent of American homes could reduce their utility bills with a heat pump, according to a 2024 study from the National Renewable Energy Laboratory, which places the median annual savings in the range of $300 to $650, depending on efficiency and weatherization.

Electric heat pumps can also help to reduce carbon emissions in every US state by up to 93 percent, while still providing two to five times more heating energy than the energy you put into it, on average. As a result, a heat pump is an environmentally friendly HVAC system that will also save you money. Most heat pumps also use inverter technology, which lets the compressor run at more nuanced and variable speeds, so you’re using only the exact amount of energy necessary to maintain comfort.

Almost any homeowner could potentially benefit from a heat pump.

Consider the case of Mike Ritter, who moved into a 100-year-old two-family home in Boston’s Dorchester neighborhood with his family in 2016. Ritter knew the boiler was running on fumes even before he bought the house, and he knew they’d have to replace it soon enough. After getting a few quotes from contractors, he was left with two options: He could spend $6,000 to install a new fossil-fuel-based system in the basement, or he could get a heat pump. Although the overall cost of the heat pump looked to be about five times higher on paper, the heat pump also came with a $6,000 rebate and a seven-year, zero-interest loan to cover the rest of the cost, thanks to Massachusetts’s statewide incentive program to encourage heat pump conversion.

Once he did the math—comparing the costs of natural gas with those of electricity, as well as factoring in the environmental impact, alongside the monthly payments—the choice was clear.

“Honestly, we were shocked that we could do it,” said Ritter, a freelance photographer, after four years of heat pump ownership. “We don’t make doctor or lawyer money, and we wouldn’t have expected to be the kind of people with central heating and cooling in their house. But there’s a million ways you can spread out the costs and get rebates and get energy credits. It’s not much more than what you’re already spending on energy right now.”

Despite all the benefits, as recently as 2021 there were still more Americans buying one-way ACs or other inefficient systems than there were buying heat pumps each year. After all, when your old system fails, it’s logical to simply replace what was there before, as the Ritters might have. We hope this guide can help you plan and budget for a true upgrade. Otherwise, you’ll be stuck with another inefficient, carbon-intensive HVAC for the next decade. And that’s not good for anyone.

I’ve been writing for Wirecutter since 2017, covering portable air conditioners and window air conditioners, room fans, space heaters, and other topics (including some unrelated to heating or cooling). I’ve also done some climate-related reporting for outlets such as Upworthy and The Weather Channel, and I covered the 2015 Paris Climate Conference as part of a journalism partnership with the United Nations. In 2019, I was commissioned by Cornell University to create a full-length play about community responses to climate change.

Like Mike Ritter, I’m also a homeowner in Boston, and I’d been looking for an affordable and sustainable way to keep my family warm in the winter. The high efficiency gas furnace in my home had been working well enough, but I knew I’d have to replace it sooner than later. I had heard of heat pumps—I knew that the next-door neighbors had one—but I had no idea what they cost, how they worked, or even how to go about getting one. This guide began when I started reaching out to contractors, policymakers, homeowners, and engineers to find the most efficient HVAC system that would work in my home, as well as to figure out what it would do to my wallet in the long run.

After this guide was first published in 2022, I ended up getting my own heat pump system installed at home. It cost around $10,000 after we factored in the various state and federal rebates and tax incentives. There weren’t even any upfront costs; we were able to cover the entire installation with a 0% interest, 7-year loan. In our first year of ownership, our annual heating costs stayed about the same, but we saved enough in cooling costs that it basically covered the loan payments. Our home is ultimately more comfortable all year round, with little to no impact on our annual budget. (As an added bonus, we also gained around 20 square feet of floor space once we removed the old radiators.)

Heat pumps in general are an objectively great idea. But the decision gets a little muddier when you try to narrow it down to which specific heat pump you should get. There are reasons most people aren’t just going out to Home Depot and bringing home whatever random heat pump they find on the shelves. You can even order one with free shipping on Amazon, but we wouldn’t recommend doing that, either.

Unless you’re already an experienced home renovator, you’ll need to find a contractor to help you through your heat pump journey—and the way that works for your situation will depend on a number of factors, including the kind of home you live in, as well as your local climate and incentive programs. That’s why instead of recommending the best heat pump for most people, we’ve come up with some basic criteria to help you navigate the process of upgrading the HVAC system in your home.

For the purposes of this guide, we’re focusing primarily on air-source heat pumps (sometimes referred to as “air-to-air” heat pumps). As their name suggests, these models exchange the heat between the air around you and the air outside. Air-to-air heat pumps are the most common option for American households and are the most easily adapted into various living situations. However, you can also find other kinds of heat pumps, which pull heat from different sources. A geothermal heat pump, for example, draws heat from a well in the ground. We have some advice to get you started on that process as well.

What size heat pump do you need?

The size you need depends on the size and layout of your home, your energy needs, your insulation, and more.

Air conditioning capacity is typically measured in British thermal units, or Btu. When you’re buying a window AC or a portable unit, you usually need to choose one based on the size of the room you plan to use it in. But selecting a heat pump system is a little more complicated than that. It’s still based, in part, on square footage—experts we interviewed agreed with the general calculation of about 1 ton of air conditioning (equivalent to 12,000 Btu) for every 500 square feet in your home. In addition, there is a set of standards maintained by the Air Conditioning Contractors of America trade association called Manual J (PDF), which calculates the impact of other factors such as insulation, air filtration, windows, and local climate to give you a more accurate load size for a specific home. A good contractor should be able to help you with this.

You also have a few monetary reasons to size your system correctly. Most statewide programs base their incentives on the efficiency of the system—after all, a more efficient system uses less electricity, which helps cut back more on fossil-fuel consumption. In Massachusetts, for example, most residents can get up to $10,000 back by installing heat pumps in their entire home, but only if the system achieves a certain performance standard set by the state. In other words, an inefficient home with an under- or oversize system could actually disqualify you from a rebate, as well as add to your monthly energy bills.

Will a heat pump even work in your home?

A heat pump almost certainly will work in your home, because heat pumps are especially modular. “They’re able to be adapted to basically every situation,” said Dan Zamagni, the director of operations at Boston Standard Plumbing, Heating, and Cooling, the company that worked on the Ritters’ house. “Whether it’s a really old home, or we’re limited by the construction we can do in people’s homes without being too disruptive—there’s always a way to make it work.”

Zamagni went on to explain that a heat pump condenser—the part that goes outside your home—can be mounted on a wall, the roof, or the ground, typically on a bracketed stand or leveling pad. Ductless systems also provide you with plenty of versatility for interior mounting (assuming you don’t already have a duct system or room to add one). Things might get a bit complicated if you live in, say, a tightly packed row house in a historic district that restricts what you can put on the facade. There are also some limits on the length of the lineset (piping) that runs between the condenser and the indoor units But generally speaking, a savvy contractor should be able to figure something out that works for you.

What are the best brands of heat pumps?

When you’re buying something as expensive and long-lasting as a heat pump, you should make sure you’re getting something from a manufacturer that has a good reputation and can provide you with quality customer support for years to come. Daikin, LG HVAC, Fujitsu, and Mitsubishi / Trane all offer warranties up to 12 years, for example, while Carrier and Rheem cover you for up to 10 years.

That being said, the heat pump you ultimately pick will likely have more to do with finding a good contractor than going with your personal preference. More often than not, your contractor or installer will be the one sourcing the parts. There may be some models that have better efficiency or distribution in certain geographic regions. And you should be confident that the contractor is familiar with this expensive equipment that they’re permanently installing in your home.

All of the manufacturers we mentioned above also have some sort of preferred dealer program—contractors that are specifically trained in their products and can provide manufacturer-approved service. Many preferred dealers also have priority access to parts and equipment. Dan Zamagni of Boston Standard, which is recognized as a Mitsubishi and Trane preferred installer, said, “We try to stick with a few brands for repetition with the installers and them knowing the equipment. Same with the sales desk, so they can all speak to this and are well trained on the products.”

Generally speaking, it’s better to find a good preferred contractor first and then take advantage of their expertise with the brands they’re familiar with. That service often comes with better warranties, too. It doesn’t do much good to fall in love with a specific heat pump only to find that no one in your area knows how to service or install it.

How do you find the most efficient heat pump?

Looking at a heat pump’s ratings can help, but don’t focus exclusively on that. Almost any heat pump offers such major advantages over traditional equipment that it’s usually not necessary to seek out the absolute highest metrics within the heat pump category.

Most heat pumps have two different efficiency ratings. The seasonal energy efficiency ratio, or SEER2, measures the system’s cooling capacity as it compares to energy use. By contrast, the heating seasonal performance factor, or HSPF2, measures heating capacity as it relates to energy consumption. The US Department of Energy recommends seeking out a higher HSPF2 in colder climates or a higher SEER2 in warmer climates.

Heat pumps that qualify for Energy Star status need to meet a certain threshold for both SEER2 and HSPF2; different states may also have their own energy-efficiency standards that factor in local climate considerations.

As with heat pump sizing, the ultimate energy efficiency of your entire home will depend on a number of factors in addition to the heat pump itself, such as weatherization and air filtration, the climate in which you live, and how you plan on using your system.

If you really want to get into the weeds, the Northeast Energy Efficiency Partnership has compiled one of the most comprehensive databases of heat pump performance efficiency in different weather conditions. Again, we would not recommend just picking the top performing model off the list, because it won’t necessarily be the best choice for your particular home, in your specific region, with the installers and service options available to you. But if you want to make sure you’re considering some decent models, the NEEP list is a good (if slightly overwhelming) place to start.

Can a heat pump work with existing HVAC ducts?

Yep, if you already have a central air system in your home, you can use your existing duct system to move the air from your heat pump. And you don’t actually need ducts: Air-source heat pumps are also available in the form of ductless mini-splits. Most manufacturers offer both options, and a good contractor can advise you on setting up different zones within your home to maximize comfort and make the best use of what your home already has installed.

Heat pumps are versatile when it comes to retrofits into existing ducting, and they can also work within a hybrid system that has both ducted and ductless units, feeding off a single condenser unit the house. When the Ritter family was upgrading their Boston home with heat pumps, for example, they used the existing air handlers to create a new ducted air system on the second floor, and then they added two ductless mini-splits to cover the office and the master bedroom upstairs, all of which tied back to the same source. “It’s a bit of a unique system,” Mike Ritter told us, “but in our case, it just ended up working best.”

In general, try to get a few different ideas from contractors about how to adapt your existing HVAC system. Doing so might save you some money, or it might not be worth the effort or expense. One encouraging factor we found in our research is that your existing system, whatever type it is, shouldn’t prevent you from getting a heat pump to supplement, offset, or replace what’s already there. You can adapt a heat pump to pretty much any home layout, as long as you (and, really, your contractor) know what you’re doing. (Case-in-point: I live on the lower level of a converted townhouse built into the backside of an old 19th-century industrial rubber mill, and we were still able to make a heat pump system work.)

Are there heat pumps that do only cooling?

Yes, but we don’t recommend such models. Sure, if you live somewhere that has a warmer climate year-round, it might sound redundant to add a new heating system to your home. But such a system is “essentially the same piece of equipment with a few extra parts, and you can make the swap with almost no extra work,” said Nate Adams, a home-performance consultant, in an interview with The New York Times. Those extra parts cost only a few hundred dollars more, and that markup is likely to be covered by a rebate anyway. There’s also the fact that heat pumps get exponentially more efficient as the home’s temperature approaches that comfort zone in the mid-60s. So on those rare days when it does drop into the 50s, the system barely has to use any energy to warm your home back up. You’re basically getting the heat for free at that point.

If you already have an oil- or gas-powered heat source that you don’t want to replace, you could install a hybrid-heat or dual-heat system that uses those fossil fuels as a backup or supplement to the heat pump. This kind of system can save you some money during a particularly frigid winter—and believe it or not, it can actually be a better choice for reducing carbon emissions (in the winter, at least). We have a separate section with more details below.

The contractor you hire to install your heat pump could be more important to your overall experience (and cost) than the heat pump itself. “As everyone’s trying to price-shop around, you can find yourself with a real low-level contractor,” said Dan Zamagni of Boston Standard. “Probably the third-biggest purchase people make in their homes is heating and cooling systems, and you wouldn’t treat a car or a home purchase in the same way. People try to nickel-and-dime that, but you do get what you pay for.” In other words, if you’re paying tens of thousands of dollars for someone to make your home more comfortable, more affordable, and better for the planet, you should make sure they do it right.

While pricing varies, a heat pump system is likely going to cost you between $8,000 and $30,000, depending on how many units you need to cover your home. There are also a wide range of rebates and tax credits available to offset that cost, including a federal tax credit covering 30% of the cost up to $2,000 under the Inflation Reduction Act. You may be eligible for other financing incentives as well, depending on where you live. And regardless of location, a heat pump can help reduce the utility bills in nearly every US household by a median amount between $300 to $650 per year, according to the National Renewable Energy Laboratory. Those savings add up over time, too.

Some anecdotal examples we’ve come across in conversation during this research:

• One member of the Wirecutter staff, in a large historic home in Pennsylvania, paid about $38,000 for a heat pump setup that included six interior mini-split units. That system supplemented an existing central heat system; the home had no central air.
• Another Wirecutter staff member, in Oregon, paid around $22,000 for three in-wall units plus a ducted system in the attic, all running off the same condenser.
• A Wirecutter staff member in Boston paid about the same price for three mini-splits and two exterior condenser units, while another Boston-based colleague spent half that for a single interior unit in a converted industrial condo complex.

These prices aren’t just for the hardware—they include labor costs and insulation, along with any specialized work such as architectural planning, wall construction, masonry installation work, and so on. While it’s a wide range, it should hopefully give you a rough idea of what to expect when you start talking to contractors.

Of course, not everyone has an easy time finding the help they need. So we’ve put together some other guidance to keep you on the path.

Know what you’re looking for at the start

The fact that you’re reading this guide already gives you a good head start. For this guide, we spoke to several contractors, all of whom told us the same thing: Only about half of their heat pump customers come to them knowing ahead of time that they’re specifically looking to install a heat pump.

“Just knowing that heat pumps are an option is helpful,” 3H Hybrid Heat Homes co-author Alexander Gard-Murray told us. “I think the most important thing consumers can do is just to actively try to get a contractor who’s up on heat pumps, who can give them a good picture of what’s available with the current models, and the current climate zones.”

That being said, we don’t recommend making all of your decisions before you find a contractor. You might have your heart set on a specific heat pump model only to find that parts and service for it are hard to come by in your area (which is especially the case in a world that’s already facing other supply-chain issues). A good contractor will know what’s available, how its performance would compare with that of more traditional HVAC options, and what’s best for the climate you live in.

Ask around for recommendations

One of the best ways to find a contractor is to find someone else who worked with a contractor they liked. If you see a friend or a neighbor with heat pumps at their home, ask them about their experience. Check your local community social media forums on Facebook or Neighbors, as well. People may even recommend that you try a different contractor, or they may offer some advice on unexpected issues that surprised them, and all of that is helpful, too.

“Find someone you know who had a heat pump installed and ask them about it,” Gard-Murray said. “Basically anyone who installs a heat pump gets really excited about it, and you start hearing more and more. It’s like an avalanche of excitement about heat pumps. I think consumer experience is the biggest thing selling them.”

Look for preferred dealers

Many heat pump manufacturers, including Carrier, Daikin, LG HVAC, and Mitsubishi / Trane, all have some kind of preferred partnership program for independent contractors. To qualify, those contractors have to meet a certain level of standards in working with the equipment and thus meet the manufacturer’s ideal expectations. If a contractor has earned this seal of approval from one or more manufacturers, that’s a good sign.

Contractors’ membership in such programs is not just a testimony to their knowledge and skill, as these contractors also tend to offer better warranties on parts and labor (and have the relationships to make sure they can get the parts they need). Although most standard Trane ductless heat pumps come with a 10-year warranty (PDF), for example, a heat pump installed by a certified Trane Comfort Specialist usually has a 12-year warranty for the equipment, plus additional coverage for parts and labor directly through your contractor.

Get multiple quotes in writing

A good sign of a reliable contractor is their willingness to prepare for you a written document detailing the potential project and costs, with no commitment or payment from you. A representative might come by your home for a site visit and give you an eyeball estimate of the project costs, but if they won’t commit it to paper—before you start negotiating—that’s a huge red flag.

Before Mike Ritter settled with Boston Standard for his heat pump renovation, the two parties went through six rounds of project proposals over the course of three months before finding one that worked. Boston Standard presented a few different ideas—ducted versus ductless systems, different zoning options, and such—as well as the costs associated with each. Those documents even included information on warranties, as well as the potential rebates that Ritter could expect once the project was done. It was that sort of attention to detail that convinced him to take the leap, despite the higher up-front cost. “We didn’t know much about heat pumps beforehand,” Ritter told us. “We were planning on just replacing the boiler, but as we talked with Boston Standard, we started to realize it might actually work to put in a heat pump and get air conditioning out of the equation, as well.”

Check the contractor’s attention to detail

Heat pump systems are impressively modular, and there should be a way to make them work in almost any home situation. But this is also your home we’re talking about, and you’re the one who will have to live with whatever changes the contractor makes to it. A good contractor should be on the lookout for any potential problems or hiccups from the very first site visit. And that means you should be getting answers to lots of questions. Are they paying attention to the amperage on the circuit breaker, for example? Are they giving you a preliminary idea of how and where they might install the units? Are their project proposal quotes accurate and detailed?

“A lot of contractors can find themselves sort of slapping these systems in without really taking the right measurements and things that should be taken into account,” Zamagni of Boston Standard told us. He specifically mentioned things such as the software the contractor uses to size your system, and whether they’re factoring in elements like windows and weatherization. There are also acoustic considerations: Although heat pumps are typically quieter than other HVAC systems, the outdoor units still have fans and compressors and other mechanical parts that could cause problems in an alleyway or next to a bedroom window. These are the sort of questions you should ask—but you should also look for a contractor who looks for things you didn’t think to look for.

Talk about the long-term investment

Choose a contractor who provides more than just labor. “Consumers should be asking contractors—and doing the math themselves—to understand the long-term savings, and not just the up-front costs,” said Alexander Gard-Murray.

A good contractor will understand the significance of this long-term investment and should be able to walk you through it, as well. Ideally, they also should be able to help you figure out how to pay for it, whether that’s by offering financing options or helping you secure one of the many, many heat pump rebates available. In addition to the federal tax credit of up to $2,000 available under the 2022 Inflation Reduction Act, there are also many statewide incentive programs available, depending on where you live. In Massachusetts, for example, the Mass Save program offers rebates for heat pump installation projects up to $16,000, depending on your income level, as well as seven-year, zero-interest loans of up to $50,000 to help cover the remaining costs, including weatherization. A good contractor should at least be aware of the full range of options available to you and help you navigate the requirements.

One other thing to keep in mind is that these funds don’t always come from the same place or arrive at the same time. Some states provide rebates at or before the point of sale, while others may require you to submit a form and wait for a check to come back to you in the mail. There are also tax-based incentives, like the credits available that come in the form of tax credits, so you might not even notice them until next April (by which point you’ll hopefully find yourself pleasantly surprised by the unexpected surplus).

Consider the full package

When you’re looking at the total cost of your proposed project, think about what you’re actually getting out of the deal. It’s not just the heat pump itself. It’s also the customer service, it’s also the warranty, and it’s also the expertise and guidance on how to make your home as energy efficient as possible. Some contractors even offer additional services, such as handling all of that complex and confusing financial paperwork. That’s a major reason Mike Ritter went with Boston Standard for his heat pump renovation: The company handled all of the paperwork as part of the proposal, which meant he didn’t have to wait around for the rebate check to process.

“We collect everything from the customer, we process the rebates for them, we submit everything,” explained Zamagni of Boston Standard. “It takes the burden away from the homeowner, who may be overwhelmed with the process overall. It helps with our whole package, so it’s basically a turnkey system for them.”

While working on this guide, I did hear a few anecdotes about people who weren’t able to get the rebates they were expecting or planning on because of some miscommunication or confusion with the contractor, or some mishandled paperwork. How often this actually happens isn’t clear, but it’s still a good reminder that some things are worth being more selective on when you hire, especially when you’re already spending tens of thousands of dollars on an HVAC system that’s supposed to last you 15 years or more.

Don’t rush into anything

“A lot of these [HVAC replacement] decisions are made under duress, like when a system fails in the middle of winter,” said Robert Cooper, president and CEO of Embue, a company that specializes in sustainable options for multi-family buildings. “You’re going to replace it with the quickest thing that you can get somebody in there. You’re not going to shop around.”

Although we can’t prevent those kinds of emergencies from happening, we can encourage you to start thinking about your future heat pump ahead of time so you’re not ending up in a situation that forces you into a 15-year commitment to an inefficient fossil-fuel heater. It’s completely normal to take a few months to negotiate over project quotes, and then again to schedule your installation based on the availability of equipment and labor. If a potential installer tries to pressure you into acting fast, especially if you’re not in a heating or cooling emergency, that’s another red flag.

Aside from living with the equipment for 15 years, you may also be entering a long-term relationship with your contractor. If anything goes wrong, you’ll continue seeing them as long as you’re covered under warranty.

It bears repeating that heat pumps in general are not only greener and more efficient than other home heating and cooling systems but also more modular and adaptable. Up until this point, we’ve tried to focus on advice that’s broadly applicable to anyone looking to buy a heat pump. But there is some other helpful information we’ve gathered in our research that could be either absolutely crucial or completely irrelevant to you depending on your situation.

Why weatherization matters

Even if you buy the most cutting-edge heat pump system available, it won’t do much if your home is drafty. Without proper weatherization, nearly 40% of heat pump owners could actually see an increase in their energy bills, according to a 2024 study from the National Renewable Energy Laboratory. These poorly insulated homes can leak up to 20% of their energy, per Energy Star. That’s not just bad for your budget; it’s also bad for the environment. In fact, just one-third of US homes are responsible for nearly 75% of all residential carbon emissions, according to the US Energy Information Administration, which has a disproportionate impact on low-income communities and people of color.

But you won’t have to worry about any of that if your home is sealed and weatherized.

Many statewide heat pump incentive programs do not merely encourage but require updated weatherization before you qualify for a rebate or a loan. Some of these states also provide free weatherization consultation services, which may include free or heavily discounted insulation and air sealing. If you live in a drafty home, this is something to look into even before you start reaching out to contractors about installing a heat pump.

What a difference an inverter makes

Most heat pumps use inverter technology. Whereas traditional air conditioners have only two speeds—completely on or completely off—inverters allow a system to run continuously at variable speeds, using only as much energy as it needs to maintain a comfortable temperature. Ultimately it uses less energy, makes less noise, and feels more comfortable pretty much all the time. The top picks in our guides to portable air conditioners and window air conditioners are all inverter units, and we highly recommend that you choose a heat pump with an inverter compressor, too.

Inverter technology also works well in conjunction with the variable efficiency of heat pump technology. You don’t have to worry about turning the system down or off when you leave the house for a while, as the system will regulate itself so well that it’ll work to maintain the temperature while barely using any energy. Turning the system on and off would actually use more electricity than just letting it run.

How heat pumps handle extreme cold weather

This is one of the most common concerns that come up when people talk about heat pumps: How well do they work when it’s cold outside? It is true that older heat pump models had a bad reputation in climates where it regularly dropped below 40 degrees Fahrenheit. But heat pump technology has improved tremendously over the years, and most modern models will continue working even in sub-zero conditions. They will, however, start to lose some efficiency as the temperature drops below freezing (though most will still be more efficient). “The colder it is outside, the harder it is for that machine to take heat from that air and move it inside,” explained Harvey Michaels, a lecturer in system dynamics and information technology at MIT Sloan. “It’s like pushing uphill.”

Put another way, it’s harder for the heat pump to move the heat around when it has to find that heat to begin with. But that’s really only a problem in extreme conditions. Even if a heat pump’s efficiency drops from 350% to 150% when it’s 5 degrees outside, it would still be more energy efficient than any other home heating method. If you want to know more, the Northeast Energy Efficiency Partnership has a comprehensive list of cold-climate-certified heat pumps; it also tracks efficiency changes at different temperatures.

If you do live somewhere that frequently experiences sub-zero temperatures, you may be able to combine a heat pump with a fossil-fuel heating system. This kind of hybrid or dual-heat system can actually help to reduce both costs and carbon emissions—but again, only in extreme conditions. If you’re not regularly dealing with sub-zero temperatures, then a good, high-efficiency heat pump should be able to warm your home on its own.

Hybrid-heat or dual-heat systems

There are a few situations where installing a new heat pump and keeping your gas- or oil-fueled burner as a backup might actually be cheaper and less carbon intensive than strictly relying on the heat pump. This kind of installation is called a dual-heat or hybrid-heat system, and it works best in places that regularly deal with temperatures below freezing. Since heat pumps can be less efficient in extremely cold weather, the idea is to offset the difference by using fossil fuels to help the room maintain a baseline temperature, at which point the heat pump kicks in to do the rest. Think of it as being similar to how a hybrid car works.

Harvey Michaels of MIT Sloan, who has served as an advisor on state and federal climate-policy commissions, expanded on the potential of hybrid heat pumps in a 2021 article. Once the temperature starts to drop below freezing, as he explains in that article, natural gas could be a cheaper option than a heat pump, depending on local energy pricing. And even if you do turn the gas on for those coldest days, you’re still reducing your home’s carbon emissions by at least 50%, so it’s still a win for the environment.

This might sound counterintuitive on the surface: How can you reduce carbon emissions by using carbon-based energy sources? But the math bears that conclusion out. If your heat pump is operating at only 150% efficiency because of the cold weather (as opposed to the 300% to 450% at which it normally operates), you’re using three times as much of the electricity to heat your home back up to the optimal performance conditions. In a state like Massachusetts, where roughly half of the regional electricity is generated by natural gas, that ends up using more fossil fuels than if you were to just turn on the gas heat in the basement. This can also help you save more money on your utility bills, particularly in sub-zero temperatures.

“Obviously we want to reduce the emissions of fossil fuels as much as possible,” said Alexander Gard-Murray, whose work on the 3H Hybrid Heat Homes report examined the way such systems can work to speed up heat pump adoption and overall decarbonization. “If you’re thinking, ‘I’ve got a gas furnace that’s newly installed, I’m not gonna rip that out,’ but you want to get a new cooling system, they can work in tandem. And that’s something else to ask your heat pump contractor about.”

Hybrid heat systems typically work best in places that regularly deal with winter temperatures below 10 degrees or so. They’re also not meant to be a permanent solution, but rather a transitional tool to help ease the stress on both the electrical grid and peoples’ wallets, while the utility companies make the shift toward a more renewable grid overall.

Up until now, we’ve been talking about permanent heat pump installations. While this is ultimately the best way to take advantage of this technology, we recognize that not everyone is able to make significant physical changes to their home. Maybe you’re a renter. Maybe you live in a condo or historic district with complicated renovation rules. Maybe your home has an extension that falls outside of your primary thermal envelope. Or maybe the price is just too steep for your budget right now. Whatever the reason, you may be wondering if there’s still a way to get the benefits of a heat pump with more flexibility, and without the help of a contractor.

The answer is: well, sort of.

In the course of our research and testing, we have come across a few portable air conditioners that offer heat pump capabilities, including our top pick, the Midea Duo MAP14HS1TBL, as well as the Frigidaire FHPH142AC1, which we also recommend. If you’re looking for a removable window option with heat pump capabilities, the Midea MAW12HV1CWT is a larger version of our top pick without the window-saving capabilities; while the Frigidaire FHWH082WA1 is a variation on our long-standing also-great window AC pick. (Gradient did release a Moderate Climate Window Heat Pump that hangs over the window without the light, but the production run was too limited for us to test, and it’s no longer available anyway.) These models all work well as temporary or seasonal heating/cooling solutions. But that’s precisely the problem: These portable heat pumps take up valuable window and/or floor space that you might otherwise want to use. That might be a worthwhile sacrifice for part of the summer or winter, but do you really want to give up an entire window through the whole spring and autumn, too?

There are some situations where that might be appropriate. Maybe you live in a place with pretty mild winters, and have a corner office or addition with plenty of windows that could use a little climate control. In that case, the Midea MAW12HV1CWT with its inverter compressor will likely be a better and more efficient option than a standard 1500-watt space heater (even if the heat doesn’t feel quite as immediately satisfying as those infrared rays). We’d still recommend weatherizing the room as best you can, however. You’ll already be leaking some air through the gaps between the insulation and the window frame, and you don’t want to waste any more energy than that.

Like traditional heat pumps, these temporary setups work best when they’re maintaining comfortable temperatures between 60 and 70 degrees, rather than actively heating or cooling a space. Once the outside temperature drops below 40 degrees or so, you might need to find an alternative heat source. But if you live in a place with a warmer year-round climate where that’s not a problem, then a portable or temporary heat pump could be a decent option.

Although this guide has focused largely on air-source heat pumps, most of the advice we’ve offered is also applicable to ground source or geothermal heat pumps. These systems pull their heat from a 6-inch diameter water-filled pipe in the ground beneath your home, and can work in most parts of the country. Soil temperature is more consistent than air temperature; it’s also typically warmer than the air during the winter, and cooler during the summer. This makes it easier for the heat pump system to extract and move the heat (and should ideally lead to more consistent electric bills, even in the face of unexpected extreme weather events).

Of course, the added convenience of a geothermal system comes with some complications: namely, that you have to install that well in your yard. Your contractor will typically either need to excavate a horizontal well about 6 feet down, according to the US Department of Energy; alternatively, you can drill a vertical well between 300 and 600 feet deep. (The actual depth and number of wells will depend on the soil and heating needs of the home.) It’s also possible to combine the pipes for several properties into one collective well. Depending on where you live, this could involve a lengthy permitting process, too (and having enough space to park a drill rig).

While this certainly adds to the cost of the project, many heat pump subsidy programs offer improved incentives for ground source installations, bringing the price slightly more in-line with their air source counterparts. For example, federal tax credits for air source heat pumps are limited to $2000, whereas ground source heat pumps qualify for tax credits up to 30 percent of the cost, with no upper limit. Geothermal heat pumps also have a longer lifespan—around 25 years on average for the hardware, and 50 years or more for the pipeline itself. The upkeep costs are typically lower, too. And again, your annual energy usage should be much more predictable.

While some air source heat pump manufacturers such as Carrier, Bosch, and Trane also produce geothermal systems, most of these systems come from dedicated companies such as GeoCool and Nordic GHP. To find a local contractor that can handle the scope of the project from drilling to hardware installation, we recommend checking out EnergySage, GeoExchange, or the International Ground Source Heat Pump Association.

• Start looking before your current system fails.
• Ask your friends, neighbors, and/or local social media groups for recommendations.
• Research local rebates and other incentive programs.
• Make sure your home is airtight and weatherized.
• Talk with several contractors, and get their quotes in writing.

This article was edited by Harry Sawyers.