Long run times are often normal
Heat pumps are designed for long, steady cycles, and in cold weather they may run almost continuously. That's only a problem if the house can't reach the setpoint, bills jump, or it happens in mild weather.
Inverter heat pumps in particular run at low speed for hours rather than cycling on and off.
Normal or a problem?
| Observation | Probably normal | Probably a problem |
|---|---|---|
| Outdoor temperature | Below about 30°F | Above about 40°F |
| Indoor temperature | Holding at the setpoint | Falling or stuck below the setpoint |
| Air at vents | Warm, steady | Cool or lukewarm |
| Outdoor unit | Running with periodic defrost | Iced solid, loud or not running |
| Electric bill | Similar to last winter's cold months | Sharply higher |
Causes of excessive run time
- Low refrigerant charge
- Dirty filter or coils
- Undersized heat pump for the home's heat loss
- Leaky or uninsulated ducts in cold spaces
- Thermostat in a drafty spot
- Large setpoint changes forcing recovery
- A failed defrost control letting ice reduce capacity
Balance point and backup heat
Every heat pump has a balance point, the outdoor temperature below which it can't keep up alone. Below it, backup heat makes up the gap.
If your system is sized well, long run times at the balance point are expected. A technician can tell you where that point is for your home.
What gets checked
- Supply and return temperatures.
- Refrigerant performance against the manufacturer's charts.
- Filter, coil and blower condition.
- Duct leakage and insulation in unconditioned spaces.
- Thermostat placement, staging and setback settings.
Setback strategy for heat pumps
Deep nighttime setbacks can backfire with heat pumps. Morning recovery calls for backup heat. Smaller setbacks, or a thermostat with smart recovery, usually save more.
Run-time FAQs
Does constant running wear out a heat pump?
Steady running is easier on a heat pump than frequent starts. Excess run time caused by a fault, like low refrigerant, does add wear.
Should I turn the heat pump off at night?
Usually not. Holding a steady temperature or using a small setback is more efficient for most heat pumps.
Next steps
Ready to get it fixed? Call (888) 555-0145 to reach a licensed provider in your area. Related guides:
Busy winter markets: heat pump repair in Maine · heat pump repair in North Carolina · heat pump repair in Virginia · heat pump repair in Washington · heat pump repair in Tennessee · heat pump repair in Georgia · all states.