Heat Pumps in a Calgary Winter: What Works Below −25 °C, and What the Furnace Still Does
A cold-climate air-source heat pump — the kind Natural Resources Canada describes as built for Canadian winters — keeps producing useful heat down to about −30 °C, though its output falls as the temperature does and supplemental heat is normally needed somewhere between −10 and −15 °C. In Calgary that supplement is the gas furnace you already own, in a dual-fuel system: the pump handles the shoulder seasons and ordinary winter days, the furnace takes the cold snaps, and a changeover temperature set for this climate decides which runs when.
The question every Calgary homeowner asks about a heat pump is the right one: what happens at −30 °C? The answer has changed in ten years. Older air-source units gave up around −10 °C, which in this city meant giving up for weeks at a time; today's cold-climate units keep working into the −20s and −30s, and NRCan's own guidance now describes them as suited to Canadian winters. What has not changed is the arithmetic of a cold snap: a heat pump's output shrinks as the air gets colder, exactly when the house needs the most, and in Calgary the sensible design accepts that and keeps the furnace.
hvaclines.ca sells and installs nothing, so this guide can say plainly what a heat pump will and will not do here. It covers what the cold-climate rating actually measures, why nearly every Calgary install is dual-fuel, where the changeover belongs and why the factory setting is usually wrong for this city, what chinooks do to the system, the electrical question in older houses, and where the money stands with no provincial rebate.
What “cold-climate” actually measures
A heat pump moves heat from outside air into the house; the colder the air, the less heat there is to move and the harder the compressor works to move it. A standard air-source unit loses most of its useful capacity by about −10 °C. A cold-climate unit uses a variable-speed compressor and refrigerant circuitry designed to keep capacity up into deep cold — NRCan's guidance puts useful operation to about −30 °C, with supplemental heating typically needed from around −10 to −15 °C down. Two numbers on the spec sheet matter more than the brochure: the capacity at −15 °C and at −25 °C (how much heat it can still make), and the COP at those temperatures (how much heat per unit of power). Below a COP of about 1.5 the gas furnace is the cheaper source in this province, and that is the real changeover.
| Outdoor temperature | Cold-climate heat pump | What runs in a dual-fuel system |
|---|---|---|
| Above 0 °C (September, April, chinook weeks) | Full capacity, high efficiency | Heat pump alone; the furnace is idle |
| 0 to −10 °C (ordinary winter days) | Good capacity, efficiency falling | Heat pump alone, or furnace on the coldest hours |
| −10 to −20 °C | Reduced capacity; efficiency near the gas break-even | Changeover zone — the setting decides |
| Below −20 °C (cold snaps) | Still runs, but output well down | Furnace carries the house; the pump rests |
Why the furnace stays
Almost every house in Calgary already has a gas furnace, gas here is cheap relative to power, and the design cold for the city is around −30 °C. Sizing a heat pump to carry a house alone at −30 °C means buying a very large unit that runs at a fraction of capacity for ten months, and backing it with electric resistance strips that are the most expensive heat there is. The dual-fuel design does the opposite: a moderately sized cold-climate heat pump sits on the furnace's plenum and shares its blower, handles the months where it is efficient, and hands over to the furnace when the cold arrives. The furnace does not go anywhere; it just works far fewer hours.
The gas saving is real but it is in the shoulder seasons — the October, March and April heating, and the mild spells between snaps — not in January. Anyone promising a heat pump will eliminate a Calgary gas bill is describing a different city.
Want a second opinion from an independent HVAC technician before you sign anything? (825) 395-7447 — the line is answered around the clock and costs you nothing.
The changeover: the setting that decides the bills
A dual-fuel thermostat holds one number that matters more than anything on the spec sheet: the outdoor temperature at which it stops running the heat pump and fires the furnace. Set it too high — many systems ship at +2 °C or so — and the furnace does work the pump could have done cheaply for most of the winter, and the heat pump you paid for is decorative. Set it too low and the pump labours below its useful range, the house never quite warms, and the power bill climbs for nothing.
The right number depends on the unit's capacity curve, the house's heat loss, and the price of gas against power that season; for a cold-climate unit in this city it is usually well below freezing, in the −10 to −15 °C region rather than near zero. Ask the installer what they set and why, and ask them to show you the capacity figures they used. A changeover left at the factory default is the commonest reason a Calgary heat pump disappoints.
What chinooks do
A chinook can lift Calgary from −20 °C to +10 °C in an afternoon and drop it back overnight. For a dual-fuel system that is the changeover crossing twice in a day — furnace in the morning, heat pump by lunch, furnace again by midnight — which is exactly what the system is for, and a correctly set one handles it without anyone noticing. Two things to watch. The outdoor unit will frost during the warm, humid hours of a chinook and run defrost cycles more often; that is normal, and a solid block of ice is not. And a thermostat with a tight cycle setting can short-cycle the furnace in the swing; the thermostat page covers the fix.
The electrical question, and the money
A heat pump needs a 240-volt circuit sized for its compressor. In the newer suburbs — Airdrie, Cochrane, the 2000s communities across the city — that is routine. In an inner-city bungalow on a 100-amp service already carrying a stove, a dryer and perhaps an EV charger, it can mean a panel upgrade, which is a real cost that belongs on the quote after a site visit, not as a surprise on install day. Electrical connections must be made by a qualified person, and a new circuit for an outdoor unit needs an electrical permit from the City of Calgary under the Safety Codes Act.
Alberta runs no provincial heat-pump rebate in 2026, and the federal Greener Homes grant and loan are closed to new applicants. Calgary's Clean Energy Improvement Program finances qualifying upgrades through the property tax bill, and manufacturer promotions of $200 to $1,500 come and go — verify any figure at source before it changes your decision. The honest way to judge the money is the shoulder-season gas saving against the installed premium over a plain air conditioner — because in Calgary the sensible comparison is never “heat pump versus furnace”, it is “heat pump versus the air conditioner you were going to buy anyway”.
Common questions
Will a heat pump heat my house at −30 °C in Calgary?
A cold-climate unit will still run and produce some heat at −30 °C, but its output is well down by then and it is no longer cheaper than gas. That is why installs here are dual-fuel: the gas furnace carries the cold snaps and the heat pump carries everything milder. A heat pump alone at −30 °C means a very large unit plus electric backup, and that is rarely the sensible design in this city.
What changeover temperature should I ask for?
For a cold-climate unit paired with a gas furnace, usually somewhere in the −10 to −15 °C region rather than near zero — but the right figure depends on the unit's capacity curve, the house and current gas and power prices. Ask the installer what they set and why. A changeover left at the factory default of a few degrees above zero wastes most of the winter's savings.
Will a heat pump replace my furnace?
In Calgary, no — it joins it. The heat pump shares the furnace's blower and ducts, handles the shoulder seasons and ordinary winter days, and the furnace takes over below the changeover. The furnace works far fewer hours, which is where the gas saving comes from, but it stays for the cold snaps.
Is there a rebate for a heat pump in Alberta?
Almost none. The Canada Greener Homes Grant closed in February 2024, its interest-free loan stopped taking applications on 1 October 2025, and Alberta offers no provincial heat-pump or furnace rebate. What Calgary has is the Clean Energy Improvement Program, which is financing repaid through your property taxes rather than money off the bill. Verify anything a contractor quotes.
Sources
Figures on this page are published market data, not our own quotes. Programmes and prices change — check each before relying on it.
- Natural Resources Canada — Electric heat pumps (cold-climate operation to about −30 °C; supplemental heat from −10 to −15 °C) — read 2026-09-12
- Natural Resources Canada — Heating and cooling with a heat pump — read 2026-09-12
- Wikipedia — Calgary, Climate (chinooks, record low −45 °C, seasonal pattern) — read 2026-09-12
- City of Calgary — Residential Clean Energy Improvement Program (financing for heat pumps) — read 2026-09-12