Will a heat pump work in my region's climate? How low can it go? Your questions answered
CBC
Canadians, especially those who heat their home by burning fossil fuels, are being encouraged to switch to electric heat pumps to cut greenhouse gas emissions.
But what parts of Canada and what temperatures are they suitable for? Do you need a backup heater? And do you need to insulate your home before installation? Here are some questions asked by CBC News readers.
A heat pump is a form of electric heating far more efficient than traditional baseboard heaters or electric furnaces. While baseboard heaters and electric furnaces generate heat from electricity, a heat pump doesn't generate heat — it simply extracts it from one place (such as outside) and moves it into spaces that you want heated.
This allows it to operate at up to 300 per cent efficiency — that is, you can get three kilowatts of heat for every kilowatt of electricity you put in.
Heat pumps also work in reverse, by moving heat out of a space rather than into it. You probably have at least one heat pump in your home for cooling — they're a key component in fridges, freezers and air conditioners.
The heat pump in your freezer can move enough heat to make it –18 C inside your freezer compartment, while making the back of the appliance feel warm. Similarly, a heat pump can heat your home by extracting heat from air outside even when the temperature is well below zero — or work in reverse, as an air conditioner during a heat wave.
That depends on the type of heat pump.
Ground-source heat pumps, also known as geothermal or geoexchange, draw heat from the ground, which tends to be a more even, above-zero temperature year-round in most of Canada. That means they operate quite efficiently even when the air temperature drops to –30 C or below.
Martin Luymes, vice-president of government and stakeholder relations at the Heating, Refrigeration and Air Conditioning Institute of Canada, said there's "lots and lots of data to show how these work consistently even in very cold climates."
It's also why they're popular in Sweden. However, they have higher up-front costs because a long heating loop needs to be installed deep enough to reach those even ground temperatures.
Air-source heat pumps extract heat from the air, and come in conventional and cold-climate models.
While heat pumps have been around for decades, cold-climate air-source heat pumps are relatively new — Kegel said the first commercial units hit the market around 2010. And previous generations of air-source heat pumps did not work well below the freezing point.
Heather McDiarmid, a climate consultant who has done lots of research on the financial and climate impacts of switching to heat pumps, puts it this way: "A car built in the 1980s doesn't look or perform very much like a car built today. And the same is true of heat pumps."
CBC News has received a number of messages from readers who have had personal experience with heat pumps installed some years ago that did not properly heat their homes — some struggled with extreme heat or cold or heated some rooms and not others, leading some people to supplement them with a wood stove, for example, to heat the rest of the house.