Air Conditioner - Not Cooling / Cold Outdoor Temperatures
Operating a room air conditioner when the outdoor temperature is 70 degrees Fahrenheit or below will limit the cooling capacity of the unit. Under these conditions it is possible for the indoor coil to frost or freeze over which limits cooling performance. The further the temperature drops below 70 degrees Fahrenheit the less productive the air conditioner becomes. This will not usually harm the unit but does waste energy.
In many cases outdoor temperatures of 50 degrees Fahrenheit or less will cause the compressor to not come on, depending upon the indoor room temperature. A cool only air conditioner is not designed for freezing outdoor conditions. It must not be used when the outdoor temperature is below freezing (32 degrees Fahrenheit). Also, if the outdoor temperature falls to 32 degrees Fahrenheit or below, any water left in the exterior pan of the unit will freeze.