I have a 2100 sf house in Florida with what I believe is a 4.5 ton 13 SEER unit. House faces East. House and AC are 5 years old. Since day one I have been betteling in the summer to get the house below 80 and the AC runs constantly. Installer says the unit is the correct size and is running properly but "It is hot outside", says I should only expect to get btw 15-20 degrees cooler than the outside air temp. I am trying to troubleshoot this from 7500 miles away as I am currently deployed in Afghanistan with the military. I also have a duffuser in the ceiling in the fron tbathroom that will build up condensation to the point of dripping, the diffuser is about 18 inches away form a skylight. Any ideas?