Emergency Heat vs. Auxiliary Heat: What's the Difference?
Heat pump owners often confuse auxiliary heat and emergency heat. Both use the same backup heating elements, but they switch on under very different conditions.
Auxiliary heat (automatic)
Aux heat turns on automatically when the heat pump can’t keep up — during cold weather, a big thermostat jump, or a defrost cycle. The heat pump keeps running; the strips just supplement it. This is normal.
Emergency heat (manual)
Emergency heat is a manual setting you switch on yourself. It shuts off the heat pump entirely and heats your home using only the backup elements.
Use it when:
- The outdoor unit is broken, frozen solid, or making bad noises.
- A technician told you to run on emergency heat until repair.
Why it matters for your bill
Emergency heat is expensive — you’re heating entirely with electric resistance, the costliest mode. Don’t leave it on as a default; it’s a stopgap, not a setting for the season.
If emergency heat is cold
If you switch to emergency heat and get weak or cold air, a backup element has likely failed. Send us your make and model and we’ll match a replacement shipped across Canada.
Related guides
- Can You Run a Heat Pump Without Auxiliary Heat?
- Heat Pump Element Replacement Cost in Canada
- How Long Do Heat Pump Elements Last?
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.