Hi Tiger, thanks for chiming in! The current Lennox G-14 is a 80,000 Btuh (I think...from reading the model numbers in the cabinet G1403-80-03. Plus another company quoted us an 80) The current AC is Goodman CKT30-1, which a quick google tells me it is 2.5 ton. We do plan to seal the duct leaks in the accessible areas of the basement, have installed interior storm windows on our huge windows, and with the addition of the R35 in the back of the house, I feel it is reasonable to go down in size. We do have considerable humidity, so for the unit to be running longer is a good thing. Returns: The current return is in the most central part of the house. There are no other hallways, so those returns will need to go on room walls. The main question is.....should we do the zoning? There isn't much room to work with in the furnace room, and they would need to do that during the install. I suppose it depends on the ducts. There's 3 main trunks, one to the bedroom portion, and two for the cathedral portion. One of those wraps around the fireplace & water heater chimneys, he did mention that that isn't ideal. We can have them come look at the ducting next week once we get the ceiling tiles down. The tax credit is listed on all three options. That does help the cost....but of course not up front. Hmmm.....not sure on the coil. It says: "Coil Type: Cased" for all three. Anything I should ask specifically about that, or which type (Looks like N or A) is better? The middle thermo is just listed as Programmable Thermostat, and is included. (quoted as $65) We could get the Thermidistat for $115....would it make much difference with the 1 stage AC? We are having the humidifier removed, we haven't needed it. It does not specifically mention the air filter cabinet, but on the last install they did for us, it was the 5 inch pleated. He did mention it when taking measurements for the quote. Again, thanks for your thoughts. Definitely helpful and giving me fodder for the next conversation with the contractor.

Ok - do you have access to existing ducts? Do you have dampers on existing ducts? You don't really need a/c downstairs, right? Because then maybe a few minisplits is the answer. Dampers are cheap (as dirt) and with some seasonal readjustment, are probably your best bet. A few new ducts perhaps to even it all out. You could put a system in that is sized to just upstairs and close all the dampers to the downstairs in the summer. Or the dampers could be mostly closed. Normally this might be an issue but if you undersize the a/c, I don't see why there would be a problem.

Terminology error on my part. Outdoor unit is 2.5 ton. Indoor portion over furnace is 3 ton. Duct work is a major problem if for no other reason, air distribution is extremely powerful in room immediately over unit and weak at other end of house. Ragarding Manual J, evidence is that prior owner of house tried to jury rig system to avoid redoing ducts. Using a larger indoor unit and large fan allowed 2.5 ton unit to survive in duct system with too low cross section. (needs the extra cooling dissipation to avoid the indoor unit freezing up.) Existing unit is inadequate in size and ducting is very inadequate. Manual J calculation just confirmed. Rule of thumb on duct sizing, while not as accurate as a manual D says duct not close to what is needed for this size house. I, so far, have talked to 5 "professionals" and am trying to get better understanding before talking to any more professionals. Obviously can fix by ripping everything out and redo. But looking for more cost effective alternative if possible.

can you please help with this. we decided the best thing to do is hook into the main HVAC for the living areas, Remove the bedroom HVAC all together. then replace the main HVAC unit with a state of the art 3 stage system (he uses american standard) Here is my question. Today in Florida it is 49 degrees! freezing for here. humidity in the house is like 20% but for some reason in my bedroom its like 60% (no ac running cuz its cold) Same floor, same type doors and windows, adjacent to living space, My room always feels damp. smells like mildew. Two mold companies have come and tested with meters to look for moisture in the floor or behind the walls and found none. I am convinced there is some sort of dampness present in this room (no carpets or drapes ) only tile, wood furniture. not much clutter, closets have been emptied into another room in prep for remediation, new roof, ducts have been cleaned, attic crawl space has been checked. HVAC unit is not dripping or clogged(that i can see, was just serviced and uv light added) the HVAC plenum is dry (although there is mold on the drywall in there) waiting for remdeation. My question is where else can i look for a moisture source? does mildew (smelling like damp towels that have sat for a while) have to mean there is a sitting water source somewhere? any other ideas. isnt it logical that if its a freezing day here i shouldnt need AC to draw humidity out of my room today?!