Heat Pump Failure: Common Causes and What to Do Next

When your heat pump, a device that moves heat into or out of your home using electricity and refrigerant. Also known as air source heat pump, it stops working, it’s not always a sign you need a full replacement. Many heat pump failures are caused by simple issues you can spot before calling a pro. Heat pumps are designed to last 10 to 15 years, but without regular maintenance, routine checks and cleaning to keep systems running efficiently, they can fail much sooner. A failing heat pump doesn’t always make noise or show obvious signs—it might just stop heating or cooling like it used to.

One of the top reasons for heat pump failure, when the system runs but doesn’t deliver the right temperature is a refrigerant leak, a loss of the fluid that carries heat between the indoor and outdoor units. Low refrigerant means the system can’t move heat effectively, even if the fan runs. Dirty filters, clogged coils, or a faulty thermostat can also mimic failure. You might think the unit is broken, but cleaning the outdoor unit or replacing a $20 filter could fix it. If your heat pump runs constantly but the house stays chilly, or if you hear hissing or see ice on the outdoor unit, those are clear red flags.

Most heat pump problems happen because of neglect, not age. People forget they need annual checks, just like a car. A technician can spot a failing capacitor, a worn fan motor, or a stuck reversing valve before they cause total failure. You don’t need to wait for a breakdown—checking your filter monthly and clearing leaves or snow from the outdoor unit can extend your system’s life by years. The good news? Many issues caught early cost less than $200 to fix. Waiting until the system dies completely often means a $5,000 replacement.

Below, you’ll find real-world guides on what to check when your heat pump isn’t heating or cooling, how to spot early warning signs, and when it’s smarter to repair than replace. These aren’t theory pages—they’re fixes people have actually used to avoid costly service calls.