How to Test Your Air Conditioning at Home

When indoor temperatures begin to rise while your air conditioner continues to run, you may have a problem with your unit. Two crucial areas in every building provide information on the how efficiently your air conditioning system is working. You need to monitor the temperature of airflow at these critical locations. Air conditioning technicians use various temperature-checking tools, and the vast majority of them choose the least expensive device.

• 1

  Launch your air conditioning test in a room located as far away from the air conditioning unit as possible.

• 2

  Insert the "probe" of a dial thermometer into or between the louvers of the cold air vent. The probe, a slim metal tube, has a bimetallic spring and a dial face attached to it. Keep the probe in the air stream for a few minutes to get an accurate reading. Remove the thermometer when the temperature indicator stops moving. Write down the cold air temperature.

• 3

  Check the temperature of the air returning to the air conditioning unit via the air return filter. Make sure you check the correct vent. Hold a facial tissue in front of the air return vent. The air returning to the system will draw and hold the tissue to the louvers of the vent. Insert the thermometer's probe into the louvers of this vent and wait until the temperature indicator needle stops moving. Write down the temperature.

• 4

  Evaluate the resulting temperatures. Optimum temperatures for cold air leaving a vent and coming into a room range from 15 to 20 degrees colder than the room temperature. The temperature of the air at the air return may range from 14 to 20 degrees warmer than air temperature going into a room.