Most Canadian homeowners exploring a heat pump are told "just get a heat pump" without anyone distinguishing the two kinds. The choice that actually matters is ground-source (geothermal) versus a cold-climate air-source heat pump, and the honest answer is that they solve the same problem in very different ways. An air-source unit is far cheaper to install and works well in most of Canada; a geothermal system costs more upfront but runs more efficiently and lasts longer, and the gap between them widens the colder your winters get. This page lays out the real differences — performance in deep cold, upfront versus operating cost, lifespan, and how Canadian rebate programs treat each — so you can tell which one fits your home.
Same idea, different heat source
Both technologies are heat pumps: in winter they move heat into your home rather than burning fuel to create it, and in summer they reverse to provide cooling. The only fundamental difference is where they get their heat. An air-source heat pump (ASHP) pulls it from the outdoor air through a unit mounted outside the house. A ground-source heat pump (GSHP, or geothermal) pulls it from a buried loop of pipe that exchanges heat with the earth a few metres down, where the temperature stays near your region's annual average all year.
That single distinction drives everything else. Outdoor air in much of Canada swings to −25°C or colder; the ground a loop reaches holds a stable 5–10°C. The heat pump that starts from the warmer, steadier source does less work for the same output.
Cold-climate performance: where they diverge
In mild and shoulder-season weather the two are close. The difference shows up in a deep Canadian cold snap. A geothermal system holds a coefficient of performance (COP) around 3 to 5 through the winter because its source barely changes — it delivers full rated output on the coldest design day. A cold-climate ASHP loses capacity as the air drops toward −25°C, its COP falls toward 1.5–2, and it diverts energy into defrost cycles. Many cold-climate installations lean on electric-resistance backup during the worst stretches, which quietly erodes their real-world efficiency exactly when heating demand peaks.
Cold-climate ASHP technology has improved dramatically and now keeps usable output to −25°C or lower on the best models — good enough for most Canadian homes. But "keeps working" and "works as efficiently as geothermal" are different claims. Over a long Prairie or Quebec heating season, geothermal's steadier COP turns into materially lower running costs.
Upfront cost versus lifetime cost
This is the trade-off in one sentence: air-source wins on the day you install it; geothermal wins over the years you run it.
- Installed cost. A cold-climate ASHP is a fraction of the cost of geothermal, which carries the expense of drilling boreholes or trenching a ground loop. For real Canadian price ranges, see our geothermal cost guide for Canada.
- Operating cost. Geothermal's higher and steadier winter COP means lower electricity use for the same heat, with the advantage growing in colder provinces and longer heating seasons.
- Lifespan. A geothermal ground loop commonly lasts 50 years or more, with the indoor heat pump rated around 20–25 years. An air-source outdoor unit, exposed to the elements, typically runs about 15 years before replacement. Over several decades the replacement cycles favour geothermal.
Which one fits your home?
There is no universally "right" answer — it depends on your situation:
- Lean air-source if: your budget is the deciding factor, you have no land or drilling access, you are in a milder zone (coastal BC, southern Ontario), or you want the simplest, fastest install.
- Lean geothermal if: you are in a cold, long-winter region (Prairies, Quebec, the North's fringe), you are replacing expensive heating (oil or electric resistance), you plan to stay in the home for many years, and you have space to drill or trench.
- Either works if: you are in a moderate climate replacing natural gas — here the decision usually comes down to upfront budget and how long you will own the home.
How Canadian rebates change the math
Rebate programs heavily influence the real cost of both. Several major programs — CleanBC Better Homes in British Columbia, Hydro-Québec's LogisVert in Quebec, and Ontario's Home Renovation Savings Program — cover both air-source and ground-source systems, and the federal Oil to Heat Pump Affordability Program (OHPA) supports either when you are switching off oil. Air-source is often the promoted default because of its lower sticker price, but some provincial programs pay more for ground-source on a per-capacity basis, which can narrow the upfront gap more than homeowners expect. Because amounts and eligibility change, check the current offers before deciding: see our Canadian rebates and incentives guide.
Want to weigh it for your province? Find geothermal installers in Ontario, Quebec, or British Columbia — and review the cost guide and cold-climate performance guide before you get quotes.
This comparison is general information, not engineering or financial advice. Equipment performance, sizing, and the right choice for your home depend on your climate zone, existing heating system, and site — confirm with a qualified installer. Rebate amounts and eligibility change; verify current programs before relying on them.