Heat pump
Also known as: heat pumps, heat pump system
A heat pump is a device that heats and cools buildings by moving heat from one place to another, rather than creating it by burning fuel.
In winter it pulls heat from outdoor air, the ground, or water and pumps it inside; in summer it works in reverse like an air conditioner. While many Canadians still assume heat pumps fail in the cold, modern cold-climate models keep working well below -20°C, which is why they've become central to home decarbonization.
Heat pump, explained at three levels
At home
Your fridge moves heat from inside the box to the coils at the back, which is why they feel warm. A heat pump does the same thing for your house: in winter it moves heat from outside air into your home, even when it's cold out.
At work
Heat pumps can cut heating energy use dramatically compared with electric resistance heating, and they replace both a furnace and an air conditioner. For buildings, that means lower operating costs and emissions over time.
At home
Efficiency is measured by the 'coefficient of performance' (COP). A COP of 3 means you get three units of heat for every unit of electricity. Baseboard heaters have a COP of 1. As it gets colder, COP drops, but cold-climate models still beat baseboards at very low temperatures.
At work
Types include air-source (ducted or ductless mini-splits), ground-source (geothermal), and water-source. Right-sizing through a heat-loss calculation is critical. Many Canadian installations keep a backup heat source for the coldest days, called a hybrid or dual-fuel system.
At home
Heat pumps use a refrigerant that absorbs heat as it evaporates and releases it as it condenses under pressure. In my opinion, the refrigerant choice is the overlooked climate issue, because some common refrigerants are powerful greenhouse gases if they leak.
At work
Large-scale adoption affects electricity grids: winter peaks rise as heating electrifies, especially during cold snaps when efficiency falls. Utilities are pairing heat pump programs with demand response, building envelope upgrades, and time-of-use rates. Refrigerant regulations are shifting the industry toward lower global-warming-potential options such as R-454B, R-32, and propane (R-290).
Real-world examples
At home
Sophie lives in Halifax and heated her house with an old oil furnace. After installing a cold-climate ductless heat pump with help from a rebate program, her heating bills dropped noticeably, and she finally had air conditioning in summer.
At work
Thomas manages facilities for a school board in Ontario. Replacing gas boilers and separate cooling units with heat pumps in two schools cut energy costs and gave classrooms reliable cooling during June heat waves.
How it compares
| feature | Heat pump | Gas furnace | Electric baseboard |
|---|---|---|---|
| How heat is made | Moves existing heat | Burns natural gas | Converts electricity directly to heat |
| Efficiency | Often 200% to 400% | Up to about 98% | 100% |
| Cooling | Yes | No | No |
| Direct emissions | None on site | Yes | None on site |
Heat pumps get more heat from each unit of energy than any furnace or heater.
For analysts
For a building owner, the business case depends on local electricity and fuel prices, rebates, and whether air conditioning is needed anyway. I'd get a proper heat-loss calculation first, because an oversized or undersized unit wipes out the savings.
History & origin
The physics goes back to the 1850s, when Lord Kelvin described the principle, and Peter von Rittinger built an early working heat pump in Austria around 1856. Refrigerators and air conditioners use the same cycle. Ground-source systems spread in the 1940s and later, but early air-source heat pumps lost much of their efficiency in cold weather. Variable-speed 'inverter' compressors and improved refrigerants changed that in the 2000s and 2010s, and the US Department of Energy's cold-climate heat pump challenge pushed manufacturers to prove performance at -15°C (5°F) in 2023 and 2024. Heat pumps outsold gas furnaces in the US in 2022, and Canadian federal and provincial programs have offered rebates to switch from oil and electric heat. In my view, the heat pump is the most important climate technology most people have never seen working.