Air Conditioner Not Cooling Well

If your room air conditioner is not cooling properly, check the following:


  • Make sure the air conditioner is properly sized for the room. For more information, see: Air Conditioners Sizing Guidelines
  • Check to make sure nothing is blocking the front of the air conditioner. When the unit is blocked by curtains, blinds, or furniture, the air flow is restricted and cooling performance will be affected.
Ambient Temperature (Environment)
  • Check outdoor temperatures. Operating a room air conditioner if the outdoor temp is 70F or below will limit the cooling capacity of the unit.
  • Check the indoor temperatures. If the room is 70 or below already, the thermostat cannot cycle the compressor on.
  • Consider the temperature of the room when the air conditioner was first turned on. If the room was very hot it will take longer to cool the room. When heat is stored up in walls, furniture, rugs and draperies, it will take longer to cool the room down. Whenever possible, turn the air conditioner on before the room heats up.
Ice on Coils/Clogged Filter
  • If there is ice on the coils, then the outdoor temperature may be below 70 degrees. The best way to prevent ice on coils is to not run the unit if the outdoor temperature is below 70 degrees F. If the temperature is close to 70 or you are unsure of the temperature, you can turn the thermostat to a warmer setting, set the fan switch to the highest position. For more information, see Air Conditioners - How to Remove Ice on Coils.
  • Make sure the air filter has been cleaned in the last 30 days. For more information, see Air Conditioners Cleaning the Filter. Filter removal and location varies depending on the individual model. Download a copy of the Owner's Manual. 
  • Check the thermostat setting. The highest setting will provide maximum cooling.
  • Cycling on and off too frequently means the unit may be oversized or the filter needs to be cleaned. For more information, see: Air Conditioners Sizing Guidelines