Why Is My AC Blowing Warm Air?

Warm air from the vents tells you the cooling system isn't doing what you expect. It doesn't tell you which part has failed.

Check the thermostat first

Make sure it's set to Cool, not Fan or Heat. A fan setting circulates room-temperature air even when nothing is wrong with cooling.

Check the filter

A badly restricted filter interferes with airflow. Inspect it before assuming the equipment itself has failed.

Look outside

When the thermostat is calling for cooling, see whether the outdoor equipment appears to be running. Don't open the cabinet or touch electrical components. You're only gathering information.

What could be happening?

Warm air can be tied to airflow, controls, electrical components, coils, refrigerant conditions, or compressor operation. A homeowner doesn't need to determine which one by opening the equipment.

When should I stop running the system?

Shut it down if you notice smoke, a burning odor, repeated breaker trips, severe mechanical noise, or another obvious electrical problem. If the basic checks don't restore cooling: Find Local HVAC Help