My central AC unit has stopped keeping the house cool. I checked the filter and it is clean. The outside part of the system is also functioning. I did notice that there was some water building up on the floor around the bottom of the system. Also, the insulated copper tube appears to be sweating; I never noticed that before. The house thermostat is set for 72 degrees, but it is reading 80 degrees and rising. Please help me and thank you.

Check your coil behind the filter. If it is full of dust and debris, it may be affecting the heat transfer.

The copper pipe should be cold, and if it is humid, water will form on the outside.

Check the air coming out of the vents. Take a thermometer (not digital, just a regular mercury one) and stick it in the vent. The iar comign out should be around 50-58 degrees.

I hate to say it, but I couldn't find the coil in the system. I was able to go check the condenser, which appears to be running fine. I was able to take off the face plates of the system, but I couldn't find any coils inside?? I turned the system off for about 16 hours, but when I started it back up it still only blew "sort of cool" air - it doesn't bring the temp down to what is programmed on the thermostat. I called a few people to come out and check it and was told over the phone it could be anywhere from nothing to thousands of dollars in repairs necessary. Also, the guy I called is charging me $90 bucks just to come look - but, I feel a little helpless because I need the air back on; it is miserable in here.

How old is the unit.
I may need to recharged.

The system is only 5 yrs old. I believe I found the problem. I was able to locate the coils (used the system diagram - duh) and cleaned out the PVC drainage pipe with some water and bleach. I think it was just clogged up because our air is back on and seemingly working fine. Thanks to all for the assist.
D