Independent guide
AC not cooling
Warm air from the vents, or the house won't get cooler. Start here.
Check these first
- Thermostat is set to Cool and the target is below room temperature.
- Replace the thermostat batteries if it has any.
- Check the air filter. A clogged one can block airflow.
- Clear leaves and debris from around the outdoor unit.
Still not working? That's a job for a pro.
When to call a pro
The system runs but still doesn't cool after these checks. Ice that comes back. A loud noise or a burning smell. Anything inside the unit is a job for a pro.
Wondering what a repair usually costs? See typical repair costs, with the source and date next to each number.
Questions
Why is my AC running but not cooling?
A few simple things can cause this. Check that the thermostat is set properly and reading the right temperature, and that the air filter is not clogged. Low refrigerant is also a common cause, and fixing it is work for a trained technician.
Source: energy.gov
Why is my AC blowing warm air?
A clogged air filter is one common reason. It holds back the air flowing through the unit, so the air coming out is not cooled well. Check the filter and replace or clean it. If the air stays warm, a technician should take a look.
Source: energy.gov
Can a dirty air filter cause an AC to not cool?
Yes, it can. A dirty filter slows the air moving through the system and makes it work harder. Check the filter once a month in hot weather, and change it if it looks dirty. If cooling does not improve, call a technician.
Source: energystar.gov
Why won't my AC turn on?
Start with the thermostat. Make sure its screen works, and swap in fresh batteries if it uses them. If the thermostat is fine, the unit's electrical controls may be worn out. That is a job for a professional, not something to open up yourself.
Source: energy.gov
Why is my AC not cooling the house?
Leaky, clogged or squeezed air ducts can let cool air escape before it reaches your rooms. Ducts are not something to open up yourself. A professional can clean them and seal the leaks, and can check the rest of the system too.
Source: energy.gov
Describe the problem
What kind of system is it?
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