And just like the previous complaint of Heat pump blowing cold air, some new heat pump owners may think their unit runs all the time because they aren't used to the longer run times and lower temperature output of a heat pump. In extremely cold weather conditions, a properly working heat pump will run almost continuously. That is the way they are designed to work.

Now, if it isn't extremely cold out (above 35 degrees) and your heat pump just seems to run all the time, then this does indeed indicate a problem. And along with this usually comes a higher than normal electric bill, lower supply temperatures, and sometimes icing of the outdoor unit.

Below is a list of possible causes. Items in red usually require a service call. Items in blue however can be addressed, some even fixed by the homeowner.

Red = Professional fix | Blue = Homeowner fix

Undersized equipment and/or ductwork
Low refrigerant charge
Refrigerant flow-related problem - restriction/bad metering device
Poor efficiency- needs cleaning and servicing
Bad reversing valve
Bad compressor valves
Compressor not running
Running in A/C mode
Outdoor unit iced-up because of a malfunction
Supplemental heat not working

Outdoor unit iced-up - weather related
Snow drift against outdoor unit
Outdoor unit not running - check breakers
Thermostat set too low
Cold return temperatures - examples: air handler in attic and the return trunk disconnected from unit, pulling in cold attic air. Unit in basement with a basement return and open windows.
Poorly insulated house, air leaks

The bottom causes in blue are commonly found problems and can be addressed by the homeowner. Try to check for these conditions first before calling for service.