AC Not Cooling? A Homeowner's Troubleshooting Guide

When your air conditioner runs but does not cool your home effectively, several issues could be at play. Here is what to check before calling for service.

Check the Basics First

Thermostat Settings - Verify it is set to "Cool" mode - Set temperature at least 3-5 degrees below current room temperature - Ensure fan is on "Auto" not "On"

Air Filter A dirty filter restricts airflow and can dramatically reduce cooling capacity. - Check filter and replace if dirty - A severely clogged filter can cause the system to freeze up

Circuit Breakers AC systems typically have two breakers—one for the indoor unit and one for the outdoor unit. - Check both breakers in your electrical panel - Reset if tripped, but do not keep resetting if it trips repeatedly

Outdoor Unit Issues

Check for Obstructions - Clear vegetation, debris, and items stored too close to the unit - Maintain at least 2 feet of clearance around the unit - Gently clean visible debris from the fins

Is the Unit Running? - Go outside and check if the fan is spinning - If the unit is completely silent, there may be a power or control issue - If you hear humming but the fan is not spinning, the motor may have failed

Indoor Unit Issues

Check for Ice If you see ice on the indoor coil or refrigerant lines: - Turn the system to "Off" and the fan to "On" - Let the ice melt completely (this may take several hours) - Check/replace the filter - After melting, try running the system again - If ice returns, professional service is needed

Check Airflow - Ensure all supply and return vents are open - Check for disconnected or damaged ductwork (in accessible areas)

Signs You Need Professional Service

- Refrigerant leaks (hissing sounds, ice buildup)

• Electrical issues (burning smell, repeated breaker trips)
• Compressor problems (unit runs but does not cool)
• Strange noises from the system
• Persistent ice formation after clearing filter

Bay Area Considerations

The Bay Area's generally mild climate means many homes can manage with less aggressive cooling. However, during heat events, your AC may work harder than usual. Ensure your system is maintained before warm weather arrives.