A heat pump needs less upkeep than a furnace, but Canadian winters ask more of it than milder climates do. Most of the job is simple homeowner work: clean or change filters every month or two, keep the outdoor unit clear of snow and ice, and make sure meltwater can drain away. Add a professional tune-up every year or two, ideally in early fall, and your system should run efficiently right through January.
Key takeaways
- Filters are the single most important homeowner task. Check them monthly in winter.
- The outdoor unit needs clear airflow and somewhere for defrost water to drain. Snow and ice buildup is the most common winter problem.
- Steam and short bursts of noise during defrost cycles are normal. Thick ice that never clears is not.
- Test your backup heat in the fall, before the first cold snap.
- Book a professional check every one to two years, before the heating season starts.
Why winter maintenance matters more in Canada
A heat pump moves heat from outdoor air into your home. As the outdoor temperature drops, the outdoor coil gets colder than the surrounding air, so moisture freezes on it. The system handles this with defrost cycles, briefly reversing to melt the ice. If airflow is blocked or the water has nowhere to go, ice builds faster than defrost can clear it, efficiency falls and your backup heat runs more often.
Cold-climate models are designed to keep heating at -25°C or lower, but they only manage that with clean coils, good airflow and correct refrigerant levels. Small neglect shows up as higher winter bills. To learn how heat pumps fit into a broader home upgrade, see our whole-home energy guide.
The homeowner checklist
Monthly (heating season)
- Check the filters. Ducted systems have a filter at the air handler. Ductless mini-splits have washable mesh filters behind the front panel of each indoor head. Rinse them, let them dry fully and reinstall. If you have pets or are renovating, check them more often.
- Look at the outdoor unit. Make sure snow, ice, leaves or a fallen tarp aren't blocking the coil or fan.
- Listen for changes. New grinding, rattling or squealing is worth a call. The whoosh of defrost and a bit of steam is not.
After every significant snowfall
- Clear snow from around and on top of the unit. Leave at least 30 cm of open space on all sides. Use a broom or brush, never a shovel edge or ice pick against the fins.
- Check the drain path. Defrost water needs to drain away and not refreeze under the unit. If ice is building up from the ground, the unit may need to sit higher.
- Watch for roof drips. Water or icicles dropping from an eave onto the unit can encase it in ice. A small roof or drip guard over the unit helps, as long as it doesn't restrict airflow.
Each fall
- Rinse the outdoor coil gently with a garden hose (power off first) to remove summer dust and cottonwood fluff.
- Clean the indoor heads' vanes and coils on ductless units, following the manual.
- Test the backup heat. Whether it's electric resistance strips, baseboards or a gas or oil furnace, confirm it switches on when called. If you're unsure which backup setup you have, our glossary explains the terms.
- Check thermostat settings. Make sure the balance point or switchover temperature is set as your installer recommended.
- Clear the condensate line on ducted indoor units so it doesn't back up.
What to leave to a professional
Some tasks need tools, training or refrigerant certification. A typical professional maintenance visit includes:
| Task | Why it matters |
|---|---|
| Refrigerant charge check | Low charge cuts heating capacity, especially in deep cold |
| Electrical connections and capacitors | Loose or failing parts cause breakdowns in cold snaps |
| Defrost control test | Confirms the unit is melting ice when it should |
| Coil and fan inspection | Bent fins or a failing fan motor reduce airflow |
| Airflow and duct check (ducted systems) | Leaky or undersized ducts waste heat |
| Crankcase heater check | Protects the compressor in very cold weather |
Expect to pay roughly $150–$350 for a visit in most Canadian markets. Some installers offer annual service plans. Most homes do well with a check every one to two years. Older systems or homes that rely fully on the heat pump benefit from yearly visits.
Winter warning signs
Call for service if you notice any of these:
- Ice that covers the whole coil and doesn't clear after a defrost cycle (usually within an hour).
- The fan isn't spinning while the compressor runs, or the reverse.
- Backup heat runs constantly in mild weather, around -5°C.
- Indoor air feels lukewarm for long stretches when it's not extremely cold out.
- A sudden jump in your electricity bill that the weather doesn't explain.
Many modern units display an error code on the indoor head or thermostat. Note it before calling, because it speeds up diagnosis.
Setting up for efficient winter operation
Good habits matter as much as maintenance:
- Avoid deep setbacks. Heat pumps work best holding a steady temperature. Dropping 5–6°C overnight can trigger backup heat in the morning. A setback of 1–2°C is usually fine.
- Use "heat" mode, not "auto," on ductless units in winter, so the system doesn't switch to cooling on sunny afternoons.
- Keep indoor heads unobstructed. Furniture and long curtains block airflow.
- Pair it with air sealing. A tighter home lets a heat pump do more with less. The Home Efficiency upgrade sequence explains why sealing and insulation usually come first.
If you're still weighing whether a heat pump suits your climate, our geothermal and heat pump overview covers air-source and ground-source options side by side.
Frequently asked questions
Is it normal for my heat pump to steam in winter?
Yes. During a defrost cycle the outdoor coil warms up briefly, and melting frost often gives off visible steam. It usually lasts a few minutes, and the fan may stop during that time.
Should I cover my heat pump in winter?
No. A full cover blocks airflow and can damage the unit if it runs. A small overhead shield that keeps falling snow and roof drips off, while leaving the sides open, is fine.
How often should I change a heat pump filter?
Check it monthly during heating season. Disposable filters on ducted systems typically last one to three months. Washable mini-split filters should be rinsed whenever they look dusty, often monthly in winter.
The bottom line
Winter maintenance for a heat pump comes down to clean filters, a clear outdoor unit and somewhere for defrost water to go, plus a regular professional check. Those habits protect the system's cold-weather performance and help keep your heating bills predictable. If you're planning upgrades, you can look up current programs for your address with our rebate finder, since provincial and utility offers change often.
Sundamentals is an independent, non-profit education platform. Program details and prices change often — check current programs for your address in our rebate finder.