Advice
Do heat pumps really work through a Quebec winter?
Yes — and here is exactly what happens as the temperature drops, without the brochure vocabulary.
What actually happens when it gets cold
A heat pump does not make heat: it moves it. It pulls energy out of the outdoor air and carries it inside.
The instinct that makes people doubt this is reasonable: “if it is −20 °C outside, there is no heat left to collect.” But it is wrong. There is still thermal energy in air well below that — there is simply less of it, and it takes more work to extract.
In practice: the heat pump does not stop. Its capacity tapers.
What “cold climate” changes
A cold-climate certified heat pump is engineered for exactly this: a variable-speed compressor that can ramp up, vapour injection, and a performance curve that holds far lower than an ordinary model’s.
Lennox’s Signature line pushes further with TruHeat technology, designed to maintain a higher supply-air temperature in deep cold.
The distinction matters in daily use. A non-cold-climate heat pump installed in Quebec will spend far more hours leaning on its backup — which means consuming at the most expensive setting the system has.
What backup heat is actually for
In Quebec, backup heat is mandatory. It is not an admission that the heat pump is inadequate: it is a safety requirement for when the temperature drops below what the unit can carry alone.
In a properly sized West Island home, the backup engages during cold snaps, not all season. Autumn, mild winter and spring heating come from the heat pump, at two to three times the efficiency of a baseboard.
If your backup runs constantly, something is wrong: undersized equipment, a badly set balance point, or overly aggressive thermostat setbacks.
The mistake that costs the most
Setting the thermostat back sharply overnight.
It is a habit carried over from furnaces, where recovery is fast and cheap. With a heat pump, jumping the setpoint several degrees in the morning triggers the electric backup — the most expensive mode in the system. You lose in an hour what you saved overnight.
The right approach is a moderate setback, or a gradual recovery managed by the thermostat. It is the kind of detail we walk through at commissioning.
The takeaway
Yes, a heat pump heats a Quebec house in winter. The question is not “does it work” but “is it cold-climate certified, correctly sized, and properly set up”. All three are the installer’s responsibility.
Read next
- What your bills look like after converting from gas to electric Your electricity bill goes up — that is arithmetic. What matters is the total of the two, and the calculation deserves to be done honestly.
- Why oversized equipment is bad equipment Oversizing is the most common mistake in residential heating, and the hardest one to fix after the fact.
Frequently asked questions
At what temperature does a heat pump stop heating?
Cold-climate certified models keep producing heat below −25 °C. Their capacity falls as it gets colder, but there is no abrupt cut-off. Older or entry-level models run out of breath considerably sooner.
Does the backup heat run all winter?
No. In a properly sized West Island home, the backup carries cold snaps — a handful of days each winter — not the whole season. If it runs constantly, that points to a sizing or settings problem.
Is defrosting normal?
Yes. In cold damp weather, frost forms on the outdoor coil and the unit briefly reverses its cycle to melt it. You will see vapour and the supply air will be cooler for a few minutes. That is normal operation, not a fault.
Let’s talk about your project
One of our advisors comes to your home, measures what needs measuring and walks you through your options — free, and with no pressure.
Monday to Friday · 8:30 a.m.–12 p.m. and 1 p.m.–5 p.m. Outside business hours, our 24-hour emergency service is reachable at the same number.