AC is Not Cooling? Here Are 10 Common Causes and Fixes.

Experiencing an air conditioner that circulates air but fails to lower the temperature can be exasperating. Swiftly identifying the problem is crucial for sustained comfort. Below, find ten prevalent reasons for AC is not cooling and their respective solutions to restore your AC’s effectiveness in keeping your home cool. These troubleshooting steps will aid in addressing the issue promptly, ensuring your indoor environment remains comfortably chilled, even during hot weather.
1. Clogged Air Filter
A dirty, clogged air filter restricts airflow and reduces cooling efficiency. Check your filter each month and replace per manufacturer guidelines, usually every 1-3 months. Use the highest MERV rating filter recommended for your AC unit.
2. Refrigerant Leak
Refrigerant is the essential substance in an air conditioning system that enables it to generate cold air. However, refrigerant leaks can significantly impair your AC’s cooling capabilities. To address this issue effectively, it’s crucial to take the following steps:
- Professional Inspection: Engage the services of a qualified HVAC technician to conduct a thorough examination of your AC system. They will use specialized tools to detect any refrigerant leaks.
- Recharge Refrigerant: If leaks are identified, the technician will recharge the refrigerant to the appropriate levels. This is necessary because low refrigerant levels can severely hamper cooling performance.
- Locate and Repair Leaks: After recharging, it’s imperative to identify and rectify the source of the leaks. Technicians employ various methods, such as UV dye or electronic leak detectors, to pinpoint these issues accurately.
- Sealing Leaks: Once located, the technician will seal the leaks using appropriate methods and materials to ensure they do not recur.
Addressing refrigerant leaks promptly not only restores your AC’s cooling capacity but also prevents further damage to the environment, as some refrigerants can contribute to ozone depletion. Therefore, timely detection and repair are essential for both comfort and environmental responsibility.
3. Frozen Evaporator Coil
If the AC evaporator coil becomes clogged with dirt and debris, it can freeze up. This blocks airflow and cooling. Shut off the AC and allow the coil to thaw. Then clean the coil thoroughly so it can cool effectively.
4. Worn Out Blower Motor
The blower motor circulates cooled air through ductwork. Old motors operate at reduced CFM airflow leading to insufficient cooling. Replace worn out blower motors so cool air is pushed optimally.
5. Short Cycling
If the AC compressor cycles on and off frequently, cooling is compromised. Have a technician check for correct refrigerant charge and capacitor issues. Short cycling strains the compressor and accelerates wear.
6. Improper Thermostat Setting
If the thermostat is not set low enough relative to the current indoor temperature, the AC won’t remain on long enough to lower the temperature appropriately. Adjust the thermostat setting as needed.
7. Dirty Outdoor Unit
Debris buildup on the outdoor condenser coils reduces their heat transfer ability, lowering cooling performance. Clean the external AC coils gently with a hose to restore proper airflow.
8. Low Refrigerant Charge
Not having enough refrigerant will make the AC blow warm air. Very low refrigerant can damage the compressor. Have a technician recharge the system to the factory-specified level to resolve insufficient cooling issues.
9. Obstructed Air Vents
Blocked air supply vents or return vents limits cooling airflow to rooms. Clean and straighten vent covers so cooled air can flow freely through the duct system and properly cool each room.
10. System Overload
Using an AC unit beyond its square footage capabilities, unusually high outdoor temperatures and insufficient insulation can overload the system’s capacity to cool properly. Upgrade to a larger capacity unit as needed.
By identifying the most common causes of insufficient cooling, you can quickly diagnose and remedy AC issues. Have a licensed HVAC maintenance technician handle any refrigerant, motor or compressor fixes for optimal performance.