Does this Sizing Make Sense?
I am replacing a split HVAC system that handles the main floor + a 15x19 room and bathroom in the basement for a total of approximately 2000 square feet. The entry and family room are vaulted ceilings. The old unit was a 3 ton 19 year old Carrier system that had always seems at least adequate in performance when working properly. I typically shut the exhaust vents in the basement during the summer since it was usually cool enough without them open. The estimates I received were mostly all 3 ton replacements of various brands based on my satisfaction with the old unit. However, two companies did load assessments and the weird part is that one told me it should be a 2 ton and the other said it should be a 3.5 ton! I tend to think the 2 ton is grossly undersized and wonder if the 3.5 ton might be too large? Anyway, here's the suggested unit based on the 3.5 ton load:
Trane XL16i 4 Ton 2 Stage, Trane XV-80 80K 4 Ton 2 stage variable speed 2 stage furnace.
Does this sound like a reasonable sizing and solution? The home is in the Atlanta area and windows are all single pane except for a french door to the deck. There is another 3 ton unit handling the upstairs but also 19 years old.
Thanks for any advice you can provide.