Why Your Heat Pump's Auxiliary Heat Keeps Running
Auxiliary (backup) heat is supposed to kick in only when your heat pump can’t keep up. If it’s running constantly, your electricity bill climbs fast. Here’s why it happens.
Normal reasons
- Very cold weather. Below roughly -10 to -15 °C, many heat pumps lean on aux heat — that’s expected during a Canadian cold snap.
- Big temperature setbacks. Jumping the thermostat up several degrees triggers aux heat to catch up quickly.
- Defrost cycles. Aux heat runs briefly while the outdoor coil defrosts.
Problem reasons
- Low refrigerant. A leak cripples heating capacity, forcing aux heat on.
- Dirty coils or filter. Restricted airflow makes the heat pump underperform.
- Faulty outdoor sensor or thermostat. Bad readings can lock the system into aux heat.
- Failing compressor. When the pump can’t heat, the strips run instead.
Where the elements come in
The heat strips themselves rarely cause aux heat to over-run — but if they’re cycling constantly, they wear faster and can fail. If a strip has already failed, you’ll get weak or cold “emergency heat.”
Need a replacement heat-strip element? Get a quote with your make and model — we ship across Canada.
Related guides
- Can You Run a Heat Pump Without Auxiliary Heat?
- Emergency Heat vs. Auxiliary Heat: What's the Difference?
- Heat Pump Element Replacement Cost in Canada
Related products
- Heat Pump Elements
- Carrier Heat Pump Replacement Elements
- Trane Replacement Heating Elements
- Goodman Replacement Heating Elements
- Rheem Replacement Heating Elements
Need a replacement element? We ship across Canada and build custom elements for hard-to-find equipment.