Everything You’ve Ever Wanted to Know About Heat Pumps (but were afraid to ask)

We're hearing more and more about heat pumps in the news. Indeed, the International Energy Agency has called them a "critical technology for heat decarbonization" and noted that most of our space heating as well as water heating needs could be met by heat pumps instead of furnaces.

To find out how all about heat pumps, including how they stack up against traditional heating and cooling equipment like furnaces and air conditioners in terms of cost, comfort, and noise levels, and how they work with ecobee smart thermostats, we caught up with Trish Long, co-founder and owner of Switch Heat Pumps.

Long explains the ins and outs of heat pumps in a way that’s easy to understand, regardless of how much you know about them. She also explains the recent innovations that have made heat pumps the best choice even in cold climates like Toronto, where Trish and her business partners have installed over 300 heat pumps since 2020.

ecobee Citizen: Please start by telling us why we should care about heat pumps.

Long: Heat pumps not only fight climate change, but they also cost less to operate than traditional HVAC equipment. That’s to say, they provide both heating and cooling and cost the same to operate as your current furnace in winter but less to operate in the other three seasons.

Because they’re extremely energy efficient, a heat pump can reduce your home’s carbon emissions by up to eight tonnes per year, which is equivalent to taking a mid-sized car off the road! That’s why experts say buying a heat pump is one of the biggest things homeowners and builders can do to fight climate change.

ecobee Citizen: How do heat pumps work?

Long: A heat pump is essentially a fancy “air conditioner” with a reversing value so that it can move heat in both directions using electricity. In summer it moves heat out of the house and in winter it moves heat in. Unlike furnaces that burn oil or gas to generate heat during winter, a heat pump works in a loop by sending very cold refrigerant outside to absorb heat and bringing it indoors to our ductwork. We tend to think of electric heating as expensive, but that’s electric baseboards which have to make heat. Heat pumps only have to move heat from one place to another via the refrigerant loop and it takes one-third the electricity to do that.

Whether you know it or not, everyone is already familiar with the technology because they’ve been in our homes for decades. Our refrigerators and air conditioners are heat pumps, but without the reversing valve.

There are other types of heat pumps, including ground-source (i.e., geothermal) and water-source, but the easiest to adopt are air-source heat pumps because they are more affordable, qualify for rebates, and easy to install.

ecobee Citizen: It was once common knowledge that heat pumps don’t work in cold climates. What’s changed?

Long: Back in the day heat pumps only worked down to 26°F (or −3°C) before switching over to the more expensive backup heating, so there’s a lot of out-dated information out there. It is no longer true that heat pumps don’t work in cold climates.

Innovation in the 1990s led to heat pumps being redesigned specifically for cold climates. Engineers perfected a way of using an inverter to move the refrigerant loop at variable speeds, which is the key to operating in cold climates. The refrigerant is what transfers the heat from outside to inside the house. With variable speeds, the heat pump can operate efficiently by running slowly most of the time, but at colder temperatures it can speed up as needed to bring more heat into the house. These modern cold-climate heat pumps are often referred to as variable speed heat pumps, but you may also hear them called inverter, variable capacity, or variable refrigerant flow (VRF) heat pumps. They continue to heat down to −30°C, at which point the backup heating elements come on.

ecobee Citizen: What different types of cold-climate heat pumps are out there, and which do you install?

Long: Most people are familiar with what we call “ductless” heat pumps. These are the ones that get mounted on an interior wall and provide heat and cooling directly to a room. They’re also called mini-split units. We mostly put these into homes with radiator heating. In a home with existing ductwork, we install a “centrally-ducted” heat pump. In this case, the heat pump replaces the existing furnace and air conditioner. We install two pieces of the heat pump, the outdoor unit and indoor unit. They pair together to provide heating and cooling, operating down to −22°F (−30°C). And even though it works that low, we put in a backup electric resistance heater just to be sure there’s enough heat on the few extremely cold days.

ecobee Citizen: What’s the cost of installing a heat pump compared to a gas furnace?

Long: In Toronto, depending on your chosen brand and size, it costs between $13,000 (Canadian dollars) and about $22,000 plus tax ($9,900 USD to $16,500 USD) to replace a furnace and air conditioner with a heat pump. That’s before the rebate of up to $6,500 CAD in Ontario ($5,000 USD).

After the $6,500 rebate, you’re looking at around $8,500 CAD for an entry-level heat pump ($6,500 USD), which is about the same cost (or less) as buying a furnace and air conditioner, and you’re getting better performance especially on the air conditioning side.

Tip: Check with your provincial or state government or local utility to see what incentives you qualify for.

ecobee Citizen: What can I expect as far as rebates, incentives, or tax credits in my state or province?

Long: My understanding is that the U.S. provides tax credits. This means at tax time you can deduct the costs of your heat pump and reduce your taxes. In Canada, we typically use a rebate system, where part of your installation costs gets refunded.

Tip: If you are in the U.S., check with your utility provider and visit Energy Star’s Federal Income Tax Credits and Incentives for Energy Efficiency to see what tax credits and deductions you are entitled to. If you are in Canada, you can find out more about your province or territories’ rebate program on the Government of Canada website.

ecobee Citizen: What’s the cost of operating a heat pump compared to a gas furnace?

Long: The cost of operating a heat pump is comparable to heating with natural gas and may cost less depending on where you live. This is despite the heat pump using electricity, which is generally more expensive than natural gas, for power. It’s able to compete on operating cost because heat pumps are roughly three times more efficient than gas furnaces.

ecobee Citizen: What about backup heat?

Long: Because it's more costly, in my experience, people worry a lot about how much backup heat they will use. But last winter in Toronto, there were only three days when we needed backup heat in my home. It doesn't come on very much, so it doesn't cost much.

ecobee Citizen: What’s the difference in cost on the cooling side?

Long: A heat pump is likely to reduce your cooling costs significantly. Even though it’s the same technology as an air conditioner, a cold-climate heat pump is designed so well that it cools much more efficiently than the average air conditioner. For example, air conditioners and heat pumps have a rating called the SEER rating, which is short for Seasonal Energy Efficiency Rating. Most homes I visit have air conditioners with a SEER of between 10 and 14. They’re an easy sell because they cost less to purchase but they use more electricity. Heat pumps have SEER ratings of 18 or higher because they are designed to be incredibly efficient. For example, even when the outside temperature is −22°F, it must efficiently heat the house to 68°. That's an 80° temperature differential! So doing some air conditioning to cool the home from 90° to 72°F is something this equipment can handle with ease. This translates into significant cooling savings.

Editor’s note: The most efficient heat pumps and AC units can cut your cooling energy use in half as compared to the least efficient models for a savings of $121 USD per year ($161 CAD).^#

ecobee Citizen: What is the first thing someone should do if they are considering a heat pump?

Long: I suggest starting with an energy audit. An energy auditor knowledgeable about heat pumps can make the process much easier, and in some jurisdictions (like in Ontario) they will also qualify you for eligible rebates and incentives.

Tip: The U.S. Department of Energy recommends checking with your state or local government’s energy or weatherization office to help you identify a qualified company to perform the audit.

ecobee Citizen: Is there any common problem you’ve seen that has an easy fix that homeowners should know about?

Long: In my previous role as an energy auditor with Goldfinch Energy in Toronto, I’d often see a problem related to uneven cooling in the summer months. I see homes with cold basements, coolish main floors, and a second floor that’s too hot. This is often caused by leaky ductwork. In the past, HVAC companies tried to deal with this problem by putting in a bigger furnace so the fan would push more air through the ductwork, but it’s not enough. With leaky ducts, too much cool air sinks out into the basement. This makes your basement cold and causes the air pressure in the ducts to drop so the top floors don’t get enough conditioned air.

There’s a very simple fix that costs $2,500 CAD. It’s called Aeroseal, which is a process that seals leaks in your air ducts from the inside for improved system performance and comfort. It can get cold air blasting out on a top floor where homeowners never thought it was possible. Of course, every home is unique, so please do your due diligence, but in the 300 homes we’ve had it done in over the years, it’s helped 299 times. There ought to be a public service announcement!

ecobee Citizen: When’s the best time to upgrade? Should I wait for my old heating equipment to break down or should I be thinking in advance?

Long: Depending on the season, we can have a four to six-month waiting list, so consider it in advance and think about doing it at during off-peak times of the year: Buy a heat pump in February.

Plus, you can often find discounted pricing in the winter too. We provide space heaters and can do an installation in two days, occasionally three. It’s temporary indoor camping for a great result—to get off gas—so our clients are pleased with it.

ecobee Citizen: What should everyone look for in an installer?

Long: Every installer will say they’ve installed heat pumps, but that doesn’t necessarily mean they’ve installed a centrally-ducted cold-climate heat pump.

People with heat pumps love them and they’re usually very happy to tell others about their experience.

ecobee Citizen: Are there any considerations around getting the right size unit that we should be aware of?

Long: Whenever there's a new technology, it's always a bit nerve-wracking because we're not as familiar with it. People often think the biggest possible heat pump will be the best choice. No one wants to be cold in winter. But it doesn't work that way with heat pumps. A bigger heat pump is actually less efficient than a smaller one.

So yes, size matters, but not in the way you think. Ensure that the heat pump and the backup heater are the correct size for your home’s heating load, not too much, not too little. That way, you'll end up with the most comfortable and energy efficient home.

ecobee Citizen: What is it like to own a cold-climate heat pump compared to owning a gas furnace? What can a homeowner expect in terms of comfort?

Long: With a furnace, it comes on, blows a lot of hot air, and then it shuts off. Then there is a period of time where we start to feel cool, at which point the furnace comes back on, and we feel the heat again.

A heat pump works a bit differently. With a right-size heat pump, the equipment runs at slower speeds for longer periods, creating a more even temperature across your home. The temperature stays very steady in the house without the temperature fluctuations of a furnace.

With the right-size heat pump, you don't notice the equipment starting or stopping all the time—and you get consistent heating and cooling.

Another advantage of the right-size heat pump as compared to a gas furnace is that because the air isn't as hot, it retains the moisture your home needs in the wintertime. So, after installing our heat pump I never re-attached our humidifier.

A third advantage of right-sizing your heat pump comes on the cooling side. The heat pump's long runtimes will dehumidify your home, making the air feel naturally cooler and reducing your cooling costs. If your air conditioner is oversized, it will run frequently for shorter periods of time, which puts wear and tear on the unit and doesn’t take out as much humidity.

ecobee Citizen: Furnaces and air conditioners can both be noisy inside the home. How does a heat pump compare on noise?

Long: With a furnace and air conditioner, you can often hear the air coming out of the registers. With heat pumps, the blower fans that distribute the air are usually smaller and so much quieter.

ecobee Citizen: What about noise from the heat pump's outdoor unit? Our air conditioner is in front of the house and when the AC unit comes on, you can really hear it.

Long: We all have a neighbor whose air conditioner kicking on causes us to groan. This neighbor needs a heat pump! Instead of blunt metal fan blades, heat pumps have curved tapered blades. The compressors are well insulated and because the outdoor fan speed is variable, most often it runs slowly and quietly. It's such an improvement that our customers often express surprise and delight at how much quieter the heat pump is. Nevertheless, in looking for a good heat pump placement location, we certainly keep in mind where people like to spend their time outdoors and try to place it away from there.

One difference to keep in mind with the heat pump is that the outdoor unit also runs in the winter because it heats the house too. We have ours in front of the house which is good because sometimes people ask, “Why is your air conditioner on in the winter?” and we have fun saying, “Well, actually, we’re heating our house with a heat pump and without gas.”

ecobee Citizen: Will my heat pump work with my ecobee smart thermostat?

Long: A lot of clients love their smart thermostats and increasingly we’re finding they play nicely with the latest heat pumps. They’ve always worked with traditional heat pumps but modern cold-climate heat pumps need an adapter to work with smart thermostats including those from ecobee. Heat pump manufacturers (and other third parties) sell adaptors that let the thermostat control the heat pump. These adapters are a piece of hardware installed between the smart thermostat and the indoor heat pump unit. Installation is technical and may involve tweaking some advanced HVAC settings, so I recommend using an experienced professional to do the job. After doing so, you can enjoy the essential benefits of a modern heat pump—especially the variable fan speeds—while getting the convenience of a smart thermostat.

Tip: Learn more about ecobee smart thermostat compatibility with modern cold-climate heat pumps in our help center.

ecobee Citizen: You’ve said that most people can install a heat pump without using a traditional furnace for backup heat. Are there any exceptions to that?

Long: Where most people live in Canada and the U.S., it’s perfectly reasonable and quite wonderful to go with just the heat pump, and there is no need for a traditional furnace. However, there are special considerations in regions with colder winters and northern communities. In places where temperatures stay below −22°F (−30°) for more extended periods, a backup gas furnace may be recommended.

Tip: There are special grants for Canadians in northern communities beyond what’s available to those living in more temperate climates.

ecobee Citizen: Why is getting off fossil fuels and getting onto heat pumps and electrification so essential?

Long: I’ve been in climate policy for 25 years, and as they say about planting a tree, the best time to do something about climate was 20 years ago. The second-best time is now.

Heat pumps are a proven technology that provide a readymade way to keep us comfortable while significantly lowering our emissions. And because they are so efficient, they can reduce our carbon emissions even if the electricity is generated from non-renewable energy sources, like coal or natural gas. This advantage in emissions will only increase as the grid decarbonizes.

Places like Maine, Nova Scotia, California, and Scandinavia, for example, are way ahead of the curve on heat pumps. There’s no question they are becoming mainstream everywhere and are definitely here to stay.

On a personal note, replacing gas heating equipment with heat pumps has helped me and many of my clients move on from feeling helpless in fighting climate change to feeling empowered because we’re cutting tonnes of carbon emissions each year.

ecobee Citizen: Are there any concerns about the capacity of our electricity grid to support the transition away from fossil fuels to heat pumps for home heating?

Long: The concern that the grid can't adapt has come up repeatedly over the past 40 years. First with solar, then electric cars, and now with heat pumps. It is a bit of a chicken-and-egg situation. But nothing will change if we only talk about it and do nothing. By embarking on wholesale decarbonization, we’re empowering the utilities to stop theorizing and start investing in the resilient, distributed grids that climate adaptation requires. We should have way more solar than we do, let’s get on with it! As heat pump installations increase, there will be plenty of time for grids to modernize.

ecobee Citizen: Anything else we didn’t cover that our readers may like to know?

Long: There are real estate agents who specialize in “green homes,” and the number one problem they face is a lack of supply. Green homes are very desirable, but they rarely come up for sale. So, it's very possible that converting to a heat pump, adding solar, or both will add to the value of your home when it comes time to sell.

Trish Long and her business partner Sara Grant co-founded Goldfinch Energy in 2020 after Long, who was then working in climate policy, had a furnace breakdown and sought a greener alternative to gas. “I was laughed out of the room,” she recalls. Goldfinch Energy became a one-stop shop for clients looking to identify heat loss in their homes and provide energy solutions.

Replacing a gas furnace or boiler with a heat pump is a surefire way to improve a home’s efficiency and cut carbon emissions. That is why Trish and business partner Mike Holm, a talented heat pump technician, started Switch Heat Pumps in 2022. Trish and Mike are putting their collective 30 years’ experience in heat pumps, climate policy and available rebates to good use, helping Torontonians open the door to carbon-free heating and cooling.

Trish's career includes roles at Evergreen Brick Works, the Pembina Institute, Trees for Life, and volunteer work at Shift: Action for Pension Wealth and Planet Health.

^*International Energy Agency, “Executive Summary – The Future of Heat Pumps”

^#U.S. Department of Energy, “Purchasing Energy-Efficient Residential Central Air Conditioners”