We had a Heat pump installed in June 2009, on the heat side it works great, but on the AC side, this is where we have the problem.
During the night and morning hours the ac seems to work all right, cannot get it below 70 degrees, and as the day warms up so does the AC unit to about 10 degrees below the outside temp, so when it goes to 100 its 90 in the house, there is cold air coming from the floor vents all day but it doesn't seem to do any good what's so ever, we have had a so called expert come out to find nothing wrong. The unit is a Alllied Air 4PHP13E24P-1 we have had the heat kit installed and also had a Honeywell PRO3000 series Themostat installed.

If the problem is during the hottest time of the day, it sounds like a insulation problem, have a tech to be there that time of day when the problem is going on