Why is my AC running but not cooling the house?

The most common causes are a dirty air filter restricting airflow, low refrigerant (usually from a slow leak), a frozen evaporator coil, or a failing capacitor.

Check your filter first — a clogged filter can cause the system to run constantly without cooling effectively. If the filter is clean and the unit is still struggling, the system needs a technician.

Running an AC with low refrigerant causes compressor damage that turns a $200 fix into a $2,000 one.