AC Running But Not Cooling House

Quick answer

If your AC runs but doesn't cool, check the air filter, thermostat settings, and refrigerant level. A dirty filter or low refrigerant can block airflow and reduce cooling efficiency. Turn off the unit before inspecting components.

Confirm the symptom

• AC fan is running
• No cool air from vents
• Thermostat set below room temperature
• No error codes on thermostat

Tools and prep

• Screwdriver set
• Thermometer
• Vacuum or brush
• Gloves
• Turn off power at circuit breaker
• Check refrigerant safety guidelines

Step-by-step troubleshooting

1. Check Air Filter
   Do: Remove and inspect the air filter for dirt or debris.
   Observe: A clogged filter restricts airflow.
   Means: Replace the filter if dirty.
   Next: Check thermostat settings
2. Inspect Thermostat
   Do: Ensure the thermostat is set to 'Cool' and the temperature is lower than room temp.
   Observe: Incorrect settings prevent cooling.
   Means: Adjust settings as needed.
   Next: Check outdoor unit
3. Check Outdoor Unit
   Do: Inspect the outdoor condenser for debris or obstructions.
   Observe: Blocked airflow reduces efficiency.
   Means: Clean the area around the unit.
   Next: Check refrigerant level
4. Check Refrigerant Level
   Do: Look for signs of refrigerant leaks (hissing sounds, ice on lines).
   Observe: Low refrigerant causes poor cooling.
   Means: Contact a professional for refrigerant recharge.
   Next: Check blower fan
5. Check Blower Fan
   Do: Inspect the indoor blower fan for dirt or damage.
   Observe: A faulty fan can't circulate air.
   Means: Clean or replace the fan if necessary.
   Next: Monitor performance
6. Monitor Performance
   Do: Turn the AC back on and observe cooling performance.
   Observe: Improved airflow or cooling indicates a fix.
   Means: If no improvement, call a professional.
   Next: End

Common causes

Parts matching

Common parts needed for this issue:

• Air filter
• Refrigerant (professional use)
• Blower fan motor
• Thermostat battery
• Condenser coil cleaner

Purchase parts compatible with your AC model for best results.

When to call a professional

• AC still doesn't cool after checking all basic issues
• Refrigerant leak suspected
• Unusual noises from the unit
• Foul odors or water leaks
• Error codes appear on the thermostat
• System is over 10 years old and frequently breaks down

FAQ

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