Why do heat pumps fail differently?
A heat pump moves heat rather than producing it, and reverses to do the opposite job in the other season. That extra capability adds components that a straight air conditioner does not have, and those are often where faults appear.
What goes wrong with a heat pump?
- Reversing valve. If the system will do one job but not the other, this is a prime suspect.
- Defrost control. Heat pumps ice up in cold weather by design and run a defrost cycle to clear it. A defrost control that is not working leaves the outdoor coil iced over.
- Refrigerant charge. Heat pumps are more sensitive to charge than many systems, and low charge means a leak to find.
- Auxiliary heat running constantly. Usually a sign the heat pump is not keeping up, which is worth understanding rather than ignoring on the power bill.
- Electrical components. Contactors and capacitors fail here as they do anywhere.
Is ice on the outdoor unit normal?
Some frost during cold weather is normal and the defrost cycle handles it. A unit encased in ice, or one that stays iced after a cycle should have cleared it, is not normal and should be looked at.
What will this cost?
$139 diagnostic, waived when you book the repair. If the outcome points toward replacement, see heat pump installation.
Repair or replace: how we weigh it
| What we look at | Points toward repair | Points toward replacement |
|---|---|---|
| What failed | A wear item such as a capacitor, contactor or fan motor | Compressor, leaking evaporator coil or cracked heat exchanger |
| Repair history | First real fault the system has had | Repairs stacking up across recent seasons |
| Condition of the rest | Remaining equipment looks sound | Several components visibly tired |
| Cost comparison | Repair sits well below replacement cost | Repair approaches a meaningful share of replacement |
| Comfort history | System kept the house comfortable until now | It never really kept up, which may be sizing or ductwork |
No formula decides this. We look at your equipment and explain what we find. See the repair or replace guide for the longer version.
Common questions
Why is my heat pump icing up?
Some frost in cold weather is normal and the defrost cycle clears it. A unit that stays encased in ice points at a defrost control, airflow or charge problem.
My heat pump cools but will not heat. What is that?
A system that will do one job and not the other often points at the reversing valve, though charge and control faults can present similarly.
Why is my auxiliary heat running so much?
It usually means the heat pump is not keeping up. That can be normal in very cold weather or a sign of a fault, which is worth establishing.
What does heat pump repair cost?
A $139 diagnostic visit, waived when you book the repair, then the repair quoted before we start.
Reviewed and updated September 2026. Prices shown are owner supplied typical ranges, confirmed after an assessment. If anything here looks out of date, call (615) 400-4993 and tell us.