What to Do When Your AC Stops Working: 5 Quick Fixes

Nothing is worse than your AC breaking down on a sweltering summer day. Before you panic or assume you need a costly repair, try these five quick fixes to get your cooling system back up and running. If your AC still isn’t working, ARCO Heating & Cooling is here to help with professional HVAC repair, HVAC installation, and HVAC maintenance in St. Charles, MO.

1. Check Your Thermostat Settings

Make sure your thermostat is set to “Cool” and not accidentally switched to “Heat” or “Off.”
Lower the temperature a few degrees to see if the AC kicks in.
If your thermostat is battery-powered, replace the batteries.

2. Inspect Your Air Filter

A clogged air filter restricts airflow, making your AC work harder—or stop working altogether.
Solution: Replace the filter if it’s dirty, which should be done every 1-3 months for optimal performance.

3. Look for a Tripped Circuit Breaker

Your AC unit relies on electricity, and a tripped breaker can shut it down.
Fix: Locate your breaker panel and check if the AC breaker has flipped to “Off.” Reset it and see if the system restarts.

4. Clear Any Blocked Vents or Registers

Blocked vents can cause airflow issues, making it seem like your AC isn’t working properly.
Check: Ensure furniture, rugs, or curtains aren’t covering vents and preventing cool air from circulating.

5. Inspect the Outdoor Unit

Your outdoor condenser unit needs space to function properly.
Clear debris like leaves, dirt, and grass that may be blocking airflow.
Pro tip: Keep at least 2 feet of clearance around the unit for better efficiency.