No chimney liner on the other bids was included?
Your chimney is an INTERIOR type. The venting tables for excluding a chimney liner under your circumstances are quite rigid.
YOU MUST MAKE SURE THAT YOUR CHIMNEY QUALIFIES
to be unlined or you will cause it to fall apart brick by brick.
OK, different parts of the country, but physics are the same.
With the 80% furnace in an unlined chimney it will sweat and cause severe damage.
I can only speak for my area(MI) the code requires a liner.
80% furnaces have been available since the early 1980s and the manufacturers were saying liners were needeed(according to the install manual)by the late 80s.
Several chimneys were reuined because there were no liners installed, and because of it became law that liners were required on every job from 1994 (in my state and many others that followed BOCA code) on.
Just because your town does not have a specific code requirement for the liner does not mean that you should forego it.
Check the install manual of any furnace company and you will see that it says they are required in cold climate.
That price you were quoted was high, I think.
Here in Mi we dont get that much for a liner.
But you will be the final decision maker. Check with the manfactuerer themselves and see what they say.
[Edited by curry on 09-30-2005 at 11:41 AM]