Heat Pump Problems: What Goes Wrong and How to Fix It

Heat pumps keep homes comfy all year, but when they act up it can feel like the weather is against you. The good news? Many issues are easy to spot and fix without tearing apart the whole unit. Below we walk through the most frequent problems, what causes them, and the steps you can take right now.

1. No Heat or No Cool – The System Won't Turn On

The first thing to check is the power. Is the breaker tripped or the fuse blown? Reset the breaker and make sure the outdoor unit has power. If the unit still won’t start, look at the thermostat. A dead battery or a wrong setting can stop the call for heat or cooling. Try resetting the thermostat, replace its batteries, and set it to the correct mode.

If power and thermostat are fine, the next suspect is the outdoor fan. When the fan motor is stuck, the heat pump can’t move air and will shut down as a safety measure. Turn off the power, remove any leaves or debris from the fan blades, and give the motor a gentle spin by hand. If it feels gritty, the motor bearings may need lubrication or replacement.

2. Poor Airflow – Rooms Feel Too Warm or Too Cold

Clogged filters are the classic culprit. A dirty filter forces the system to work harder, reducing airflow and raising energy bills. Grab the filter, check the label for replacement frequency, and replace it if it looks dark or clogged. While you’re at it, inspect the air vents in each room. Closed or blocked vents can create hot spots.

Another hidden cause is a blocked condensate drain. When water can’t escape, the system may go into a defrost cycle too often, cutting heating output. Locate the drain line (usually a PVC pipe near the indoor unit) and clear any slime with a cup of bleach mixed with water. Flush it with a garden hose to make sure water flows freely.

3. Strange Noises – Buzzing, Humming, or Clicking

Sounds often point to mechanical issues. A buzzing noise usually means the capacitor is trying to start the motor but can’t. This is a quick replacement for a qualified tech. A rattling sound can be loose panels or screws on the outdoor unit—tighten them with a screwdriver.

Clicking noises often happen during the defrost cycle. The heat pump briefly shuts off the compressor to melt ice on the coil, then restarts. If the clicks are rapid and never stop, the control board could be failing and will need professional diagnosis.

4. Ice Buildup on the Outdoor Coil

Ice on the coil is a sign the defrost cycle isn’t working right. Check that the outdoor unit has enough clearance (at least two feet) and isn’t covered in snow or leaves. A dirty coil can also freeze; spray it with a garden hose on low pressure to remove dirt. If the problem persists, the defrost timer or sensor may be faulty and should be inspected by a technician.

5. High Energy Bills – The Pump Is Running Forever

Running nonstop usually means the thermostat can’t sense the set temperature or the heat pump’s sensor is dirty. Clean the indoor coil with a soft brush and vacuum. Also verify that doors and windows are sealed; drafts force the system to run longer.

If you’ve tried all the above and the pump still behaves oddly, it’s time to call a professional. Refrigerant leaks, compressor issues, or electrical faults require specialized tools and certifications.

Keeping an eye on these common heat pump problems can save you time, money, and a lot of frustration. A quick filter swap, a cleared drain line, and a bit of outdoor cleaning go a long way toward keeping your home comfortable year‑round.