The air is cool but doesn't seem cold enough
If the air doesn't seem cool enough it is necessary to use a thermometer to check the difference in temperature between the air going into the unit and the air being blown into the room. Ideally, the temperature difference should be more than 15 degrees. For example, if the temperature going into the air conditioner is 80 degrees, the temperature coming out of the unit should be at least 65 degrees or less. If the difference is 15 degrees or more there is probably no cause for concern. If the temperature difference is less than 15 degrees you should check the following:
Check to make sure the air damper is closed. If it's open, it will bring in outside
air and reduce the efficiency of the unit.
During the winter season many people cover their air conditioners
to protect the unit from the weather. In the spring or summer they will sometimes forget to remove the cover. If your unit has a cover on the outside portion of the air conditioner remove the cover first.
The condensing coils will always be on the "warm" side of the air conditioner. That is, on the side that faces outside of the room to be cooled. Air is drawn into the back of the air conditioner on the sides through vent slots and is blown directly out through the condenser coils. If the coils get clogged with lint, dust and dirt the cooling system cannot provide the cooling necessary. To clean the coils it will be necessary to remove the entire cover of the air conditioner or pull it out of the wall to gain access to the coils. They can be cleaned by blowing compressed air at them or by using a soft bristle brush to wipe the dirt off. It is important to also clean any dirt or lint build-up in the bottom of the air conditioner so the condense water
will be picked up by the condensing fan slinger properly.
It could also mean that you are trying to cool too big an area for the size of the unit.
AREA TO BE COOLED / CAPACITY (BTU/HR)
100 to 150 square feet = 5,000
150 to 250 square feet = 6,000
250 to 300 square feet = 7,000
300 to 350 square feet = 8,000
350 to 400 square feet = 9,000
400 to 450 square feet = 10,000
450 to 550 square feet = 12,000
550 to 700 square feet = 14,000
700 to 1000 square feet = 18,000