Thanx Teddy Bear.

The original system was 3 and the house was never less then 80 in the summer, we made the jump hoping to at least be comfortable. We got no warning of the dangers of doing so. The guys who came out the other day told us the ducting was sized for 2 or 2.5, so it appears someone else already upsized before we purchased, and we upsized their upsize, just compounding the problem.