Common Causes
- Excessive ice buildup on the outdoor unit
- Low refrigerant
- Reversing valve stuck in cooling mode
- Thermostat set to emergency heat unnecessarily
- Aging or undersized system struggling in extreme cold
What You Can Try
- Check for heavy ice buildup on the outdoor unit — a light frost is normal, thick ice is not.
- Confirm the thermostat is set to "Heat" and not stuck on emergency heat.
- Replace the air filter if needed.
- If the system still isn't producing heat, call for service — heat pumps rely on precise refrigerant levels and valve operation that require a trained technician.
If these steps don't resolve the issue, stop troubleshooting and call a licensed technician — repeated restarts or DIY repairs on gas or electrical components can be unsafe.
