I've been reading alot here and have quite a few questions. My current system is a 10 year old Carrier 12 seer 2.5 ton package unit. It is undersized on the a/c and oversized on the heat. I have ran the hvac calculator and that gave me a lot to think about. I want to upgrade sometime in the future, just not now. Will I be able to keep the existing duct work if I go to a 3 ton 13 or 14 seer dual fuel heat pump? Current sizing is 16in. return, 20x25 filter grille, and a 16in. supply trunk that branches off what looks like 10 or 12in. lines that feeds 2 rooms. All end up at 6in. lines to each room. I did the cfm and line size tool on the calculator just to check but that just added to the questions. One other thing, my t-stat is in the hallway near the return. There is no register there, does it need one? I was thinking of having one installed if it will be helpful. Just trying to be prepared and informed when the time comes. For now I'm going to see about more insulation and adding window film to the south and west windows. One other thing I noticed my unit doesn't have a trap on the condensate drain. I guess they didn't put one on cause it's at ground level on the slab. How important is it to have one put on?
[Edited by jl1 on 07-30-2006 at 08:53 PM]