What Should I Do If My Heat Pump Stops Working?
Run five safe checks before you call anyone: confirm the thermostat is set to heat with working batteries, check both breakers — indoor air handler and outdoor unit — look at the air filter, clear snow or ice from the outdoor unit, and give a steaming unit 10-15 minutes — it may just be defrosting. If the house is getting cold, switch to emergency heat while you troubleshoot.
Five safe checks when a heat pump stops working
| Check | What it rules out | Time |
|---|---|---|
| Thermostat on heat, batteries replaced | A dead or mis-set thermostat calling for nothing | 2 minutes |
| Both breakers — indoor and outdoor units | A tripped circuit cutting power to half the system | 3 minutes |
| Air filter | Airflow so choked the system shuts itself down | 2 minutes |
| Outdoor unit clear of ice, snow, and debris | A blocked coil that can't pull heat from the air | 5 minutes |
| Wait out a possible defrost cycle | Normal steaming and pausing mistaken for failure | 10-15 minutes |
Work the checklist: thermostat, breakers, filter, outdoor unit
Start at the thermostat because it fails quietly — dead batteries or a mode bumped to "cool" mimic a broken heat pump. Next, find both breakers: most systems run two circuits, one per unit, and homeowners routinely miss the second. Reset a tripped breaker once, fully off then on. If it trips again, stop — that's an electrical fault that needs same-day heat pump repair in Frederick, not a third reset.
Then go outside. A Frederick cold snap can frost the outdoor coil, and the unit will steam and pause its fan for 10-15 minutes while it defrosts — that's normal. Ice caked over the whole cabinet, snow drifted against the coil, or leaves packed into the fins are different: clear what you can reach by hand and let the unit recover.
- Check both breakers — the outdoor unit's circuit is the one people miss.
- One breaker reset only; a second trip means call, don't reset.
- Light frost plus steam is a defrost cycle — wait 15 minutes before judging.
Stay warm, and know when to call
If the checklist doesn't revive the system, flip the thermostat to EM heat. In most homes, emergency heat still works when the heat pump fails because it runs separate backup strips — pricey on Potomac Edison rates, but it keeps pipes and people safe. If the system stays dead, one careful hard reset of the heat pump is a reasonable last try before calling.
Call for service when the outdoor unit is dead while the indoor blower runs, when a breaker won't hold, or when the system runs but never warms the air. That first pattern — indoor alive, outdoor silent — often traces to a blown fuse in the outdoor disconnect, and naming the symptom when you book speeds up the visit.
- A house below 60°F with no heat is a same-day call, especially with kids or older adults home.
- EM heat costs 2-3x more to run, so use it as a bridge, not a season.
- Note what you already checked — it shortens the technician's diagnosis.
Questions homeowners ask next
What Should I Do If My Heat Pump Stops Working?
Check the thermostat mode and batteries, reset a tripped breaker once (there are two — indoor and outdoor), replace a clogged filter, clear the outdoor unit, and wait out a possible defrost cycle. Switch to emergency heat if the house is cold, and call if nothing responds.
Why is my outdoor unit steaming and not running?
That's almost always a defrost cycle. The heat pump pauses its fan and melts frost off the coil, steaming for 10-15 minutes before restarting on its own. Steam is normal; a unit encased in solid ice is not.
How long can a house go without heat in winter?
In a below-freezing snap, indoor temps can hit the 50s within hours, and below about 55°F pipe-freeze risk starts climbing. Use emergency heat as the bridge and treat a fully dead system as a same-day call.