Contract Traps, Failures and Official Sources
Heat pump installation problems in Canadian winters: causes, signs and fixes
Common heat pump and furnace installation failures in Canada, from oversizing, snow and ice and poor defrost drainage to refrigerant leaks and wrong controls, and how to get them fixed.
Most heat pump complaints in Canada trace back to installation and setup, not the equipment: units sized from the old furnace rather than a heat loss calculation, outdoor units placed where snow and roof runoff bury them, defrost water freezing on walkways, refrigerant charge set by guesswork, ducts too small for heat pump airflow, and controls that call on backup heat far too often. The good news is that many of these are fixable without replacing the equipment, if you can describe the symptom clearly and the installer's warranty is still in force. This guide pairs each common symptom with its usual causes and what to ask for.
This guide is part of HVAC problems and official sources.
Symptoms and likely causes
| Symptom | Likely causes | What to ask the installer |
|---|---|---|
| Heat pump turns on and off every few minutes in mild weather | Oversized unit; thermostat settings; refrigerant charge | Heat loss calculation used; check charge and cycle settings |
| House cold on the coldest days; high electricity bill | Undersized for design temperature; backup not wired or locked out; low airflow | Capacity at design temperature; backup configuration |
| Electric bill much higher than estimated | Backup strips running too often; aggressive setbacks; wrong switchover in a hybrid system | Backup lock-out temperature; thermostat staging; data from the thermostat |
| Outdoor unit covered in ice that does not clear | Defrost fault; blocked drainage; snow buildup; roof water dripping on the unit | Defrost check; raise the unit on a stand; move it away from drip lines |
| Ice sheet on walkway or driveway | Defrost meltwater draining onto paved areas | Relocate drainage or the unit |
| Noisy ducts or registers | Ducts too small for heat pump airflow; high static pressure | Static pressure test; duct changes |
| Loss of capacity after months | Refrigerant leak at a flare or brazed joint | Leak test, repair, documented recharge |
| Water dripping indoors | Condensate line blocked, frozen or not sloped | Condensate route; heat tape or rerouting |
| Ductless head blowing cool air in winter | Defrost cycle (normal, brief); settings; low charge | Explain the defrost cycle; check charge |
| Furnace and heat pump running at the same time | Incompatible thermostat or wiring in a dual-fuel setup | Control configuration |
Winter-specific installation details
Snow and ice. The outdoor unit should sit above the expected snow depth on a stand or wall bracket, out of the path of snow sliding off the roof and water dripping from eaves. Units under a roof edge without eavestroughs are a classic source of ice buildup.
Defrost drainage. Air-source heat pumps periodically melt frost from the outdoor coil. That water must drain away freely and not refreeze around the base or across a walkway.
Wind and drifting. Units on the windward side of a house can fill with drifting snow. Ask about placement or a wind baffle where drifting is common.
Line sets. Long or poorly supported line sets and badly made flare connections can leak refrigerant. A proper installation includes a pressure test and evacuation, and the commissioning report should note them.
Worked example: when the backup heat is the real cost
Illustrative: a homeowner's January electricity use rose by 1,400 kWh compared with the contractor's estimate. The thermostat's history shows the 10 kW backup strips ran 160 hours that month, mostly in the morning after a night setback of 5 °C.
- Backup energy: 10 kW × 160 h = 1,600 kWh.
- If the heat pump had supplied most of that heat at a COP of 2.5, it would have used roughly 1,600 ÷ 2.5 = 640 kWh.
- Difference ≈ 960 kWh, or about $144 at an illustrative $0.15 per kWh, in one month.
The fix may be as simple as a smaller setback, a slower recovery setting or a lower backup lock-out temperature, at little or no cost. Ask the installer to adjust it under the labour warranty, and track the next month's use.
Furnace and boiler installation failures
- Orphaned water heater venting after a mid-efficiency furnace is removed from a shared chimney.
- Condensate lines from condensing furnaces or boilers freezing where they run outside.
- Intake and exhaust terminals too close to windows, other vents or snow level, which codes regulate.
- Short-cycling boilers oversized for the heat loss or without outdoor reset control.
- Carbon monoxide risk from poor venting or combustion; every home with fuel-burning appliances should have working CO alarms, and many provinces require them.
If you smell gas, leave the home and call your gas utility's emergency line from outside.
How to get it fixed
- Document the symptom: dates, outdoor temperatures, photos of ice or snow, thermostat history, bills.
- Call the installer in writing and reference the labour warranty. See warranty registration.
- Ask for a commissioning check: refrigerant charge, static pressure, airflow, control settings, and for gas appliances a combustion test.
- Get a second opinion from another licensed contractor if the first one will not fix it, and keep their written diagnosis.
- Escalate: for unsafe gas work, the provincial safety authority (for example TSSA in Ontario or Technical Safety BC); for contract disputes, the routes in how to complain.
Before buying, the quote and contract checklist covers snow clearance, drainage and commissioning, and the sizing guide explains how to avoid size problems.
FAQ
Is steam from my outdoor unit in winter a problem?
Usually not. It is typically the defrost cycle melting frost from the coil. Repeated thick ice that never clears is a problem.
Should I cover my heat pump in winter?
No, not while it is in use for heating. Keep it clear of snow and ice instead. Follow the manufacturer's instructions.
How do I know if the refrigerant charge is right?
A technician measures pressures and temperatures against the manufacturer's charging method. Ask for the readings in the commissioning report.
Sources
- Natural Resources Canada — air-source heat pump guide: installation and operation
- TSSA (Ontario) — fuel safety and carbon monoxide
- Technical Safety BC — gas safety in British Columbia
- HRAI — installation training and standards
- CSA Group — gas installation code CSA B149.1
