Hmm, for a $250 ANNUAL heating cost, how does going to 90% save me $84/yr??




With a 60 percent furnace you are spending 250 bucks but only getting
150 worth of heat[250*.6] A 90 percent furnace would use 166 of gas to
output 150 worth of heat[150/.9] so 84 a year. 93 percent 5 bucks more.


I am NOT a person to disconnect, unseal, and remove an old unit (now an
80% model), suport the AC plenum, put the new unit in, attach gas,
electricity, thermostat, plumb out the combustion exhaust air, reattach
to the AC plenum, and seal it all up. This is several hundred dollars of
installation costs.

the assumption in your post that you could not buy a 60 percent furnace
is that you are buying a furnace, thus the comparison is only valid
apples to apples, new furnace to new furnace, not new furnace to nothing.


20 years is just about average here with heating degree days of 1263.
Rust is the most common failure mode. We just don't hardly use them.


condensing furnaces should not rust


In your climate a superinsulated house would be a better return, you
should never need heat. My moderately well insulated house does not drop
below 68 on a 32 degree night. could save the cost of the furnace and
the gas