"Sexytom976" wrote in message
oups.com...
Same reason a Chevy Cavalier is cheaper to fix than a Cadillac.

The 80% does NOT have a sealed combustion chamber (90+) do.
(this can be a good thing though)

Did you ever look at the complextiy of a 90+ unit, more sensors,
and more things can fail.

I don't think you have looked at a new 80% either! The 80's are pretty close
to the 90% furnaces in complexity. If you compare a 30 year old 80% to
todays furnaces, sure there is a big differance. The current 80% furnaces
are just as full of controls as the 90% units. Heck, I think all 80%
furnaces hace inducer motors now, at least I have not seen any current
production 80% that are natural draft.
The only differance between a 80% and a 90% these days is that 90's are
condensing, so you have to deal with condensate drainage.
Greg