Will Emergency Heat Work If the Heat Pump Is Not Working?
Yes — in most homes, emergency heat works even when the heat pump is dead. Flipping the thermostat to EM heat bypasses the failed outdoor unit and runs your backup heat source instead: electric resistance strips in the air handler, or the gas furnace in a dual-fuel setup. The catch is cost — strips draw 2-3 times the power of the heat pump, so EM heat is a bridge to a repair, not a way to live.
Heat pump heating modes: what runs and what it costs
| Mode | When it runs | Cost to run |
|---|---|---|
| Normal heat pump | Everyday heating down to about freezing | Lowest — the baseline |
| Auxiliary (aux) heat | Engages automatically when the heat pump can't keep up in a cold snap | High while running — strips assist the heat pump |
| Emergency (EM) heat | You switch it on manually after a failure | Highest — 2-3x normal, strips carry the whole load |
| Dual-fuel furnace backup | Takes over below a set outdoor temperature or on EM heat | Moderate — gas costs less than electric strips |
Aux heat vs. emergency heat: same strips, different trigger
Two settings use the same hardware. Auxiliary heat engages automatically: when a below-freezing Frederick snap drops the heat pump's output, the system adds the strips to help. Emergency heat is the manual version — you flip the thermostat to EM heat yourself, which locks the outdoor unit out and puts the strips on full duty.
That manual switch is exactly what you want when the outdoor unit is broken. A failed compressor can't get worse if it never runs. On Potomac Edison rates, though, strip heat can add several dollars a day — which is why it pairs with a call for emergency heat pump repair rather than a wait-and-see approach.
- Aux heat = automatic assist during cold snaps; EM heat = manual switch after a failure.
- EM heat stops the outdoor unit from running, which protects a damaged compressor.
- Dual-fuel homes burn gas on EM heat — cheaper than strips, still worth a prompt repair.
Using emergency heat the smart way
Before you settle in on EM heat, rule out the simple stuff. A tripped breaker, dead thermostat batteries, or an iced-over outdoor unit can mimic a full failure — the checks worth doing when a heat pump stops working take about ten minutes. If the unit went quiet after a power blip, one careful power-cycle reset of the heat pump sometimes brings it back without a service call.
Once you're on EM heat, drop the thermostat a couple of degrees and close off unused rooms — every degree matters at strip prices. And if the outdoor unit is dead while the indoor blower runs fine, the signs that point to a blown disconnect fuse are worth knowing before the technician arrives.
- Set the thermostat 2-3 degrees lower on EM heat to blunt the cost.
- Don't switch back to normal heat mode until the repair is done.
- If EM heat also blows cool air, the strips need service too — call same-day.
Questions homeowners ask next
Will Emergency Heat Work If the Heat Pump Is Not Working?
Usually yes. Emergency heat runs your backup source — electric strips or a dual-fuel furnace — and bypasses the failed outdoor unit completely. It keeps the house warm at 2-3x the cost, so use it as a bridge until the repair.
How long can I run emergency heat?
Mechanically, indefinitely — the strips are built for continuous duty. Financially, days rather than weeks: strip heat draws 2-3x the power of the heat pump and shows up clearly on a Potomac Edison bill.
Why is my emergency heat blowing cold air?
Either the strips aren't energizing — a tripped air handler breaker is the common cause — or the thermostat isn't actually in EM heat mode. Check the breaker first; if the air stays cool, the backup heat itself needs service.