I have a builder grade Comfort Maker single stage furnace that has a
bad heat exchanger. It is 5 1/2 years old and still under warranty.
The part is free, but install is $1500. They gave me the option of
replacing, or installing a new Trane 2 stage furnace for $3500. They
said that I could save $500-$700 per year with the 2 stage. I have dual
zone heating with the second Comfort Maker furnace in the attic. It is
working fine. Is it worth having the better furnace installed, or is
the guy blowing smoke? I have used this HVAC company for many years,
but I know nothing about HVAC except change filters and service twice
per year. The total heating area is approximately 3300 square feet. Any
help would be appreciated.

Drewink