Old system: 2004 model year Rheem 3.5 ton A/C unk SEER (likely 12 or 13) & gas furnace 80% AFUE Proposed new system: Amana 3.5 ton single stage A/C 16 SEER & gas furnace 96% AFUE. Lifetime warranty heat exchanger, compressor (Copeland scroll), and condensor coil, 10 yrs on evap coil and all else. $5890 after utility company rebate and $500 federal 1040 income credit. Includes running new refrigerant lines and two new thermostats one for upstairs zone one for downstairs. Also includes running new flue since the high efficiency gas furnaces apparently use a PVC flue on account of condensate build-up (flue temp does not exceed 120 F). He offered two different dual stage (A/C) systems for more money but since selling the house soon I'm not inclined to install a bells and whistles system. I have requested an estimate from local Trane contractor but no one is calling me back since Tuesday (It's now Saturday).