Heat Pumps
Address the largest source of emissions in your home by switching all or some of your home heating to a heat pump.
What do Heat Pumps Look Like?
The outdoor part of a heat pump looks like a slim-style air conditioner. Depending on the heating needs of your home, it will be one or two fans stacked on top of a snow stand or mounted on the wall. The fan needs three feet of clear space in front of it but can be hidden on the top, back and sides.
Inside, a centrally ducted heat pump system will be a metal box that replaces your furnace or, in a hybrid system with a gas furnace providing some back-up heating, the indoor component will be hidden in the ductwork on top of your furnace.
For homes without ductwork, wall, floor and ceiling installed heat pumps are also available.
How do Heat Pumps Work?
We’re all familiar with heat pump technology because our refrigerators and air conditioners are heat pumps. An air source heat pump is really just a fancy air conditioner that can also run in reverse to bring heat inside during the winter.
Refrigerant lines connect an outdoor unit to one or more indoor units. In the winter, the refrigerant is colder than outdoor air temperature as it goes outside so it is able to absorb heat from the surrounding air as it runs though the outdoor unit. It then goes through a compressor - causing the refrigerant to get very hot. When the hot refrigerant passes through the indoor unit(s), the heat is released into the house. The cooled refrigerant then goes back outside to absorb more heat.
Because the amount of energy needed to pump and compress the refrigerant is relatively low compared to the amount of heat energy that is moved into the home, heat pumps can often be 300% efficient. That means they can provide three units of heat energy for every one unit of electricity used.
Can Heat Pumps Work in Canadian Winters?
Air source heat pumps work in winter because even when it feels cold to us outside, there is plenty of thermal energy in the air. Although they’ve been in use for more than 50 years, recent innovations have resulted in new cold climate models that make them ideally suited for use in Canada. This class of heat pump can work down to -27°C to -30°C.
Can a Heat Pump Have a Gas Back-Up?
In Ontario, it is possible to have a fully electric heat pump system but some people choose a hybrid heat pump system where they use a gas furnace for heating on the coldest days or months of the year. There are different hybrid configurations so it is important to work out the details to ensure that your emissions and operating cost goals will be met.
Can a Heat Pump Provide Cooling during the Summer?
Heat pumps provide both heating and cooling. Even if your furnace is relatively new, if you are looking to install a new air conditioner, a heat pump is an excellent alternative as it will take the place of the air conditioner and will also take on some or, potentially, all of your home’s heating depending on how it is sized.
Operating Costs
Many Ontarians still think that heating a home with electricity is prohibitively expensive but that’s not the case with heat pumps. Baseboard heating can be expensive but, in contrast, air source heat pumps are more affordable to run because absorbing heat from the outside air and moving it inside requires much less electricity than creating the heat the way a baseboard heater does. Due to the recent increase in gas prices, appropriately-sized heat pumps cost slightly less to operate than a gas furnace and unlike gas they do not produce on-site greenhouse gas emissions.
Sizing Considerations
Heat pumps should be sized to account for the heat loss of your home. This includes measuring the dimensions of the home and factoring in insulation levels, window details and airtightness (measured using a blower door test). Duct size is also a factor in determining the optimal heat pump size and duct airflow can be tested to better understand this factor.
Heat pumps can include back-up electric heating which can operate at the same time as the heat pump to provide a heat boost during the coldest weather. This resistance heat back-up should be part of the overall heat pump system sizing. If back-up electrical is installed, it may require an electrical upgrade.
Ground Source Heat Pumps
Horizontal or Vertical
Ground source heat pumps take heat from the ground in the winter and replace it during the summer while cooling your home. Because the ground temperature about 2m below the surface stays consistently warm year round, it is a more cost effective option to grab this heat using a horizontal loop. Alternatively, vertical heating and cooling loops can be drilled several hundred feet down if a large horizontal area isn’t available.
Best Suited to Farms or Larger Properties
Ground source heat pumps are a very efficient way to heat and cool a home. If you are building a new home, or you own a property with plenty of space (like a farm or cottage), a ground source system may be the perfect option. It has higher upfront costs but lower operating costs and longer expected lifetime.
Due to the space required, it is unusual to be able to install ground source systems on a standard city lots.