proposal #1
1169031 Active Systems PERFORMANCE 15 PURON HP CARRIER AIR CONDITIONING 25HPA536H30 FV4BN(B,F)005 36000 13.00 15.50 36000 9.00 21800
you get a little better heating eff with the larger air handler. see below.
1125695 Active Systems PERFORMANCE 15 PURON HP CARRIER AIR CONDITIONING 25HPA536H30 FV4BNB006 36000 13.00 16.00 36000 9.30 21800
of course, both qualify for the tax credit.
ductwork should be evaluated since you are going up in size.
you do want the Carrier thermidistat with either of these systems.
IMO