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All about Heat Pumps

The heat pump is a basic component of home energy efficiency upgrades. Whether your priority is greater home comfort, lower utility bills, or fighting climate change, the heat pump is something you should definitely consider. 

What exactly is a heat pump?

A heat pump is a remarkable piece of equipment that can heat and cool a home using very little energy. First invented in the mid-1800s, heat pumps move heat from one location to another in the same way as our fridges, freezers, and air conditioners…but the heat pump that you install in your home can move heat in two directions. In winter, it pulls heat out of the air or ground outside and moves it into your home, while in summer, it takes heat from your home and moves it outside. Because it simply moves heat from one place to another, it uses much less energy than systems that burn fuel to create heat. 

Why you should make the switch

Many of the first people to adopt heat pumps were motivated by concern over the carbon pollution produced when we burn fossil fuels like fossil gas (traditionally referred to as ‘natural’ gas to enhance its public image). More than half of Toronto’s greenhouse gas emissions come from buildings, and most of those are generated by the fossil gas burned to heat them. The desire to reduce greenhouse gases and to be kinder to the planet continues to be a major motivating force, but people are starting to recognize the other advantages of heat pumps. 

They deliver a steady stream of warm or cool air instead of the less-regular on-off cycles of other modes of space heating and cooling. Air, walls, floors and furniture maintain a steady temperature without cooling off, making your home more comfortable. 

A heat pump can replace both your furnace or boiler and your air conditioner…feed two birds with one seed! 

Heat pumps are quieter than air conditioners.

Heat pumps don’t produce toxic carbon monoxide as do systems burning fossil fuels. 

Many homeowners—especially those who have also invested in improvements to their house’s walls and roof—find that the change to a heat pump has resulted in lower utility bills. While electricity bills will likely grow, gas bills will fall or disappear. If you get off gas completely, you can disconnect from the gas supply and save the fixed connection fees. Just make sure to have the gas meter removed and have your account permanently closed. 

As more people switch over to heat pumps and away from fossil gas, the gas utility will have fewer customers to cover the fixed cost of maintaining their gas infrastructure. Many homeowners want to get ahead of the curve, so they are not among the shrinking number of gas customers left to share the fixed costs of the gas provider. 

Are all heat pumps the same?

The short answer is no. They all use the same principle of moving heat from one place to another, but the place they get the heat and the way they distribute the heating or cooling can be different. Some homes may even use more than one type of heat pump.

Most heat pumps in Toronto are air source heat pumps (ASHP), meaning that they obtain their heat from the air. Within this category, you will hear of regular or conventional heat pumps and cold climate heat pumps (ccASHP), which are able to gather heat at lower temperatures. 

 

Conventional ASHPs are adequate for milder climates like Vancouver.For a Toronto home, they may also be sufficient for a very well-insulated house, if paired with another heat source like your existing gas furnace in a hybrid system (more on this later), or if you really like wearing sweaters. 

 

Cold climate heat pumps are a bit more expensive than conventional heat pumps due to their more-complex design, but their higher efficiency leads to operational savings in the long term. They are probably the best solution for most Toronto houses, and the only ones you should consider if you want to get off gas completely. 

You may also hear about ground source heat pumps (GSHP), which get their heat from the ground. These devices are relatively expensive and require considerable ground space for heat collectors. For this reason, they are impractical for most private Toronto houses and are not the focus of this discussion. 

 

The second thing to look at is how the heating or cooling might be delivered. In Toronto, most houses have either ducts or radiators. Prior to heat pump technology, in ducted systems, air has been heated by a gas furnace or cooled by an air conditioner and then moved through the house in ducts usually hidden in walls and ceilings. A house with radiators has used gas to heat water in a boiler, and the hot water has been distributed through the house in pipes and radiators. A radiant system also uses hot water to heat floors and/or ceilings. A shrinking number of houses still use electric baseboards for heating without ducts or radiators. 

If your house has ducts…

If your house has ducts, you will probably want to continue to use a ducted system to distribute air heated or cooled by the heat pump. You will likely have a central unit that serves the entire house. The condensing unit of the heat pump will be installed outside either on a raised platform or attached to an outside wall (like a conventional air conditioner). An air handler inside, where your gas furnace was, will circulate the warm or cool air. 

If your house has radiators or radiant floor heating…

In this case, you have two choices: 

If you want to keep your hot water distribution system, you can opt for a “hydronic” system. Homes equipped with boiler systems and radiators or radiant floor heating can use an air-to-water or, less frequently, a ground-to-water heat pump system. The water circulating in these systems will be at a lower temperature than with a boiler, which may, sometimes, require size upgrades to the radiators and the distribution systems.  

 

When you use a heat pump to replace a hydronic boiler, the same heat pump can also preheat your hot water, then only requiring a small boost of electric heating to bring the water up to shower temperature. 

 

Rather than cooling water for a radiant system in the summer, which will lead to puddles of condensation in your house, for cooling, consider adding a second air-to-air heat pump which can be placed in your attic with small ducts to cool the upper floor, where it is needed the most. This heat pump will also dehumidify your home, which is a large part of the cooling process. As a bonus, this second heat pump can be switched on to ‘heating’ mode for those few really cold days in the winter, providing you with a back-up heat if you need it. 

  

If you choose not to keep your hydronic system, you can opt for a ductless system. 

If you choose a ductless system…

This is the system you will use if your house doesn’t have ducts and if you choose not to retain your hydronic system with its radiators or radiant floors. This system uses “mini-split” or “multi-split” units mounted on walls or ceilings, similar to wall-mounted air conditioning units that have been used for years. The number of indoor units you need will depend on your home’s size and layout. Sometimes small duct systems are added to allow one indoor unit to serve multiple rooms. These are called “ducted mini-splits.” One outdoor unit can serve one or several indoor units depending on the configuration. One important advantage of this type of system is that you can maintain different temperatures in various parts of your home. 

If you want to keep your gas furnace as back-up…

If you have a newer forced-air gas furnace, or you’re not ready to give up a gas furnace, you can pair it with many types of heat pumps in what are called “hybrid” or “dual fuel” systems. These systems use the heat pump until the outside temperature drops below a set temperature or until the heat pump is no longer able to deliver the heat required to meet the temperature you’ve set on your thermostat. At this point, the system switches automatically to the fossil fuel heating system. The homeowner has complete control over the system and can switch to the gas furnace if they’re uncomfortable. There are even some hybrid systems that can be programmed to switch between heating systems based on whether you want to minimize carbon emissions or utility costs. 

Diagram of a hybrid system with a heat pump and gas furnace

If you only want one specific area heated or cooled…

Small air source heat pump units can be mounted into a window opening, much like the air conditioners we’ve used for years. These units are less efficient than central and ducted systems, but they plug into a regular household power outlet and can effectively heat or cool a room. 

Still have questions?

Of course you do! Here are some of the frequent questions we hear about heat pumps.

Do heat pumps work in our cold climate?

You may be wondering if a heat pump will function properly in Toronto’s climate. The answer is yes: there are a range of heat pump technologies that are up for the task. Just look at Norway, where 60% of homes are heated with a heat pump despite their cold climate. Modern cold climate air source heat pumps (ccASHPs) are designed to operate efficiently down to temperatures as low as ‘actual’ minus 30 to minus 40 degrees Celsius, rather than ‘windchill’. Fortunately, Toronto’s temperatures never go down that far, rarely even with the wind chill. Furthermore, an electric resistance heater can be added to the system if you’re nervous about shortfalls. 

 

Will I need to upgrade my electrical service or buy a new panel? 

Some contractors and electricians will say that you should always upgrade your electrical service before installing a heat pump. Your electrical service provides the amount of electricity, measured in amps, your home can draw from the grid. Increasing your electrical service is like installing a bigger pipe of electricity into your home. Some older Toronto homes have 60-amp services and were designed for a time when we used far fewer electric appliances. Many homes have 100-amp services which, based on actual usage patterns, is likely more than enough for most homes - especially now that we have switched away from incandescent light bulbs. Still, some homeowners are being told they need a 200-amp service just to get a heat pump. Unless there are multiple rentals, your home is very large, or you will be charging multiple EVs at the same time this assertion should be double-checked. 

 

In short, if you have a 60-amp service you may need to upgrade it, but it will be a good investment for the future of your home and its resale value. If you have a 100-amp service, you likely don’t need to upgrade it. Before spending thousands of dollars unnecessarily, have your electrician check your Historical Usage Data through Toronto Hydro’s ‘Green Button’ https://www.torontohydro.com/for-home/green-button to determine your current maximum amperage usage. Then subtract the uses that will be removed and add the uses that will be added through your upgrade, to determine your required electrical service size. 

If your home has old knob-and-tube wiring, you should certainly have it replaced. Knob-and-tube wiring lacks the capacity for today’s levels of power use; they are subject to mechanical damage in accessible areas. Because they’re often overloaded, they’re seen as a fire hazard which, beyond being a safety concern, can greatly limit home insurance coverage and your home’s resale value. 

Will all heat pumps work in my old, uninsulated house?

Yes, they will—they will just have to work harder! Your gas furnace has to work harder too, by the way. The answer the HVAC contractor likely came to was to oversize your old furnace for your home. This is an additional level of inefficiency many gas furnace installations produce. For a drafty, uninsulated home, a cold-climate heat pump can still match the warmth of a furnace, but you will likely want some electric resistance heating or a hybrid system to cover the coldest days of the year. 

The great thing is that with a small investment in air sealing and some strategic insulation, you can transform a drafty home and lower your heating bills dramatically. When you do this your heat pump will be happy to carry the load all by itself. 

Are heat pumps noisy?

We hear this question a lot—more than we hear our heat pumps, actually. 😂 Although older heat pumps may be as noisy as your neighbour’s old AC unit because of the fan inside these systems, modern heat pumps have become far quieter. Still, it makes sense to find a good site for the outdoor unit. Perhaps away from your (or your neighbour’s) bedroom window if anyone is a light sleeper. Also, attaching the unit to a wall can cause more vibrations and noise than one installed on the ground. 

 

Are heat pumps worth the price?

Yes. Next question? 

Okay, fine, we certainly think they are! Nearly every heat pump owner who has had a good installer and has learned how to use their system properly will agree. A heat pump is a major upgrade to your home’s comfort and air quality with additional safety and cost benefits. For the price, it makes very good sense to modernize your HVAC equipment with a heat pump whenever you get the chance. 

You will pay more upfront for this better experience. There are rebates and financing programs that often bring this price down dramatically—a new heat pump for the same cost as a replacement furnace, that’s a win! But heat pumps will often win out on operating costs too, bringing your total cost of ownership down, especially if you cut your gas line and not be paying for your gas connection every month. 

Warm bedroom floors in the morning, cleaner air, no threat of carbon monoxide poisoning, no pollution leaving your home, we think it’s well worth the price. 

Who can I get to install and maintain my heat pump?

Any HVAC contractor who plans to be in business in the next 15 years. We wish we could say all HVAC contractors have seen the light but some of them, especially those who have been around enough to “see it all”, have gotten so comfortable with installing gas appliances they aren’t ready to retool for the next advance in HVAC. It’s not that we don’t appreciate the skill and experience of HVAC professionals, but some are doing a disservice to their customers by not staying up-to-date and giving them the best advice. 

What you really want isn’t a contractor who will grumble as they put in your heat pump. You want an installer who knows the ins and outs of these systems and makes them an important segment of their business. If you are using a Retrofit Advisor, they will often offer referrals to HVAC contractors who fit the bill. HRAI has a Heat Pump Champion Advocate program: https://portal.hrai.ca/ContractorLocator (be sure to select Heat Pumps in the Service Type). Your neighbours who are happy with their heat pump may be willing to make a referral too. 

 

What kind of maintenance do heat pumps need? How long do they last?

While heat pumps use the same, reliable technology as your air conditioner, they still require maintenance to keep operating at their best. The outdoor units need to be placed in the right location as snow, vegetation, debris, and pet urine can all interfere with good operation. These outdoor units can also frost over in winter and, when they go through their defrost cycle, the puddled water can refreeze and become a slipping hazard if not collected or redirected. 

If your heat pump uses air ducts and a fan, they will use the same air filters as furnace systems, and these will need occasional replacing. Just like a regular check-up your old gas furnace gets, having your installer or other qualified contractor inspect your unit regularly will keep the system running efficiently. Expect them to do the following: 

  • Check the refrigerant lines for leaks to see if it should be recharged with new refrigerant gas. 

  • Inspect and clean all electrical connections, motors and moving parts. 

  • Clean the condenser and evaporator coils and check the condensate drain for clogs. 

  • Check and tune the blower for homes with air ducts or the pump for those with radiators. 

  • Check the thermostat and control devices to ensure the heat pump is being used efficiently.

 

What happens in an electrical blackout?

The first thing to keep in mind is that, for safety reasons, even gas systems like furnaces will stop operating during a power outage unless connected to a battery or generator. If your system uses air ducts, the heat is distributed through your house by an electric fan and if you have radiators, it’s by an electric pump. A heat pump will just require more battery backup or a backup generator to operate. For the majority of homeowners, you won’t be able to tell the difference between being a heat pump owner and a furnace owner. Except we suspect heat pump owners will have more stylish sweaters and way more working flashlights. 

 

If everyone switches to a heat pump, won’t it crash the electrical grid?

When does Toronto’s grid struggle and have brown outs? Usually, it’s in the middle of a summer heatwave when everyone is running their AC full tilt. Many of those old, inefficient units are taxing the electrical grid with unusual demand. Modern, more efficient heat pumps will help with this problem dramatically. 

Since our grid is designed to operate during the summer peak, we have an enormous capacity with today’s grid to swap furnaces for heat pumps in our lower-demand winter. Even as thousands of Torontonians install heat pumps, we will not be overstraining our grid. Also, since electrification is the future, Ontario power agencies and Toronto Hydro have plans to aggressively scale our electrical grid to keep our homes and businesses running. 

Will my household insurance be affected if I get rid of my gas furnace?

Some insurance companies may change insurance premiums based on a homeowner’s decision to install a heat pump. Some insurers seem to have the backwards notion that piping an explosive and deadly gas to burn in a metal box is somehow less risky than a heat pump!

It’s always a good idea to report changes to your home’s heating and cooling system to your insurer. If you get any pushback or your agent tries to use this as an opportunity to raise your rates maybe it’s time to shop around… 

This article draws in part from the Canada’s Home Electrification Toolkit. Written by Heather McDiarmid, Building Decarbonization Alliance. Illustrations by Saje Damen. Copyright © 2024 The Building Decarbonization Alliance. This article and the Toolkit have been released under a Creative Commons CC BY-NC-SA license.

© 2024 by Toronto Home Retrofits.

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