My 17-year-old Carrier furnace has a cracked heat exchanger. I have
received three different quotes that I would like advice on please.

My house:
built in 1989, under 1700 sq. ft., rancher on slab, vaulted ceiling in
great room with two skylights, three bedrooms, 75,000 btu gas furnace
in attic

quotes:
- Amana AMS8 70,000 btu 80%, warranty 20, 5, 2 $3349 (the guy who came
on the service call)
- Lennox G40 70,000 btu 80%, replacement 2.5 ton evaporator coil, same
warranty, $3300
- York Choice or Trane XB, 20,5,1 warranty, $2400 or with replacement 3
ton coil $3500

I plan on being in this house another 1-2 years.