My contractor proposes a 5 ton BTU SEER 13 AC onto existing furnace with new 5 ton coil, lines thermstat, pad, wiring for $3590. My Toledo, ohio, 15 year old home (and furnace) is 3500 sq feet . The old furnace ( 92% efficient?) works Ok, maybe a little noisy with its single stage fan.

The SEER 13 wouldnt qualify for Tax Credit. Contractor says cannot fit High Eff unit onto existing system . The Tax Credit would mean a lot.

He would also install 12000 BTU 95% eff. Tappan furnace with 2 stage heat and variable motor with all the trimmings for additional $3890.

What do you think of installing just the new AC? Should the 15 year old furnace be replaced also? Price sound reasonable.