Summary: Your AC is running but the house stays warm. This frustrating problem has a dozen potential causes — from simple fixes you can do yourself to issues requiring a professional. We break it all down.
Check These First (DIY)
1. Thermostat Settings
Set it to COOL and at least 5°F below current room temperature. Ensure it's not in emergency heat mode (heat pump systems).
2. Clogged Air Filter
A dirty filter restricts airflow over the evaporator coil, causing it to freeze and stop cooling. Replace the filter, turn the AC off for 2 hours to thaw, then restart.
3. Blocked Condenser Unit
The outdoor unit needs clear airflow. Remove debris, overgrown plants, or anything within 2 feet. Rinse the coil fins gently with a garden hose from the inside out.
Issues That Require a Pro
4. Low Refrigerant (Freon Leak)
Refrigerant doesn't consume itself — low levels mean there's a leak. Signs include ice on the refrigerant line, hissing sounds, and dramatically reduced cooling. Adding refrigerant without fixing the leak is just a temporary patch.
5. Frozen Evaporator Coil
Caused by restricted airflow, low refrigerant, or dirty coils. You'll see ice buildup on the indoor unit. The coil must fully thaw before resuming operation.
6. Failed Compressor or Capacitor
The compressor is the heart of the AC — if it fails, you get no cooling whatsoever. A bad capacitor prevents the compressor or fan motors from starting. Capacitor replacement is affordable; compressor replacement is more significant.
If the outdoor unit isn't running at all but the indoor air handler is, the problem is almost certainly electrical — capacitor, contactor, or wiring. Call us and we'll diagnose it fast.
Need Professional HVAC Help?
Chicago Service HVAC's NATE-certified technicians are ready to help. Same-day appointments available.
Call (773) 231-8486