Air Conditioning - central air not cooling during heat of day

Hi, I'm hoping someone can give me some insight into a problem with my central air. During the heat of the day if my thermostat is set at 68 degrees the temperature in the house may be as high as 80 degrees. In the morning when I get up the thermostate says 68 degrees and so is the temperature in the house. I've had the a/c recharged and it did not solve the problem. Any suggestions, other than replacing the outside unit and the a-coil. Both units I currently have are about five years old. Please help!!! Thanks for all your input.

Sounds like you have a problem! If unit is sized correctly it should be able to cool with out side temps at 80! 68 is pretty cool did they size it to be able to cool to 68 degrees?

I don't know. It is a 2 and a half ton unit for a 1300 square foot house. What do you think?

Central A.C. systems DO NOT need recharging unless there is a leak somewhere. They come factory pre-charged and the refrigerant lines connecting the outdoor and indoor units are brazed...there should be NO loss of refrigerant unless the install job was not done right.

Adding refrigerant will not help you get more cooling (unless the unit was indeed low in refrigerant, in which case the leak MUST be found and fixed). A refrigerant overcharge will do exactly the opposite, it will make the refrigerant less cold and you will get less cooling.

a 2 1/2 ton unit for a 1300 ft2 home sounds about right, but of course it will depend of how good is the insulation in walls and roof, as well as type of windows you have there. Also, we've had a couple of brutally hot days...it is too much to expect a unit to keep 75F or less when it's 100F outside. Most certainly not 68F. No A.C. system is sized to maintain 68F, they are sized to maintain 75F at "design outdoor conditions"...For central NJ, for example, design OD temps are 89F, so a unit that keeps a home at 75F when it's 89-90F outside is doing was it is expected of it. Some oversizing will help keep 75F indoors when the outdoors is even higher, but too much oversizing is NOT a good thing.

You may have some other issues as well. Is this an attic mounted unit? Is the duct system sheet metal and perhaps not insulated? Is it leaky? When was the last time the outdoor coil was pressure washed and with a coil cleaner? Has someone taken the time to check the charge using industry standard procedures? How well is the thermostat performing, is its location appropriate?

A good easy check for a HO to do is to check the dry bulb temp at the return grille face and then check the dry bulb temp at the supply vent that is closest to the unit. Post your test results for examination immediatley.