I have a 2 story house around 2900 Sq ft. Downstairs cools fine.
Upstairs I try to keep at 74, but it just goes up to 78-80 during a hot day. I have measured the attic temp and it gets around 110-120 on average during the hot days. I have good insulation and power vents in about a 20 year old house.
The AC unit was installed new in 97, it is a 3.5 ton with a 4 ton A coil. I had my AC guy out today to look at it. He says I am only getting about 6-8 degrees of cooling. It is 75 in here now and it is putting out around 67. He said everything loos good, clean and working right but it should be colling better than that. The pressures were "textbook". He has done this for a while and has said he had not seen anything like it. He was so perplexed he didnt even charge me to come out.
Anyone have any suggestions? This is the second guy I have had come look at it and not be able to do anything sort of suggesting I replace the unit.