What to watch for
- Air from the vents is warm or only slightly cool.
- Airflow is weak even with a clean filter.
- Grinding, squealing or banging from the indoor or outdoor unit.
- The system turns on and off in short bursts.
- Musty or burning smells when it runs.
- Energy bills climb with no change in how you use the system.
What you can safely check
Make sure the thermostat is set to cool and the filter is clean, and that the outdoor unit has clear space around it. Never open the electrical panels on the equipment yourself.
When to call
If a quick check does not fix it, or you see ice on the lines, water around the indoor unit or a tripped breaker that keeps tripping, turn the system off and call a technician. Running a failing system can turn a small repair into a large one.