Air Conditioner Heat Pump Not Working?

If your air conditioner heat pump has suddenly stopped working—especially in the middle of a sweltering summer or a freezing winter—you’re not alone. Many American homeowners rely on heat pumps for year-round comfort, and when they fail, it’s more than inconvenient—it’s stressful. Before you call a technician, there are a few things you can check yourself.

1. Check the Thermostat First

It might sound obvious, but sometimes the issue is as simple as a thermostat setting. Make sure your thermostat is:

Set to the correct mode (heating or cooling)

At a temperature different from the current room temp

Running on “Auto” or “Heat/Cool” and not just “Fan”

Dead batteries or a faulty thermostat could also be the culprit.

2. Inspect the Air Filter

A clogged air filter can reduce airflow, strain the system, and cause the unit to shut down or run inefficiently. Replace your air filter if:

It looks dirty

It hasn’t been changed in over 90 days

You notice weak airflow

This small fix can make a huge difference.

3. Look for Ice on the Coils

If you see ice forming on the indoor or outdoor coils, turn off the system immediately. Ice build-up is often caused by:

Low refrigerant levels

Poor airflow due to blocked vents or a dirty filter

Mechanical issues

Let the ice thaw completely and then see if the system restarts normally. If it ices up again, call a professional.

4. Check the Outdoor Unit

Head outside and inspect the condenser unit. Is it:

Covered in leaves, debris, or snow?

Making unusual noises?

Completely silent?

Make sure it has at least 2 feet of clearance all around. Sometimes the problem is as simple as a tripped breaker or a disconnected power supply.

5. Reset the System

Many systems have a reset button or can be restarted by turning off the power at the breaker for a few minutes and then switching it back on. This may clear minor issues or error codes.

When to Call a Pro

If you’ve checked all the above and your air conditioner heat pump still isn’t working, it’s time to contact a licensed HVAC technician. Potential issues could include:

Low refrigerant or a leak

Faulty reversing valve (the part that switches from heating to cooling)

Bad capacitor or contactor

Compressor failure

Final Thoughts

A malfunctioning air conditioner heat pump is more than just a comfort issue—it can affect your health, your home, and your wallet. Performing regular maintenance and staying alert to early warning signs can help you avoid costly emergency repairs.