My home is a small brick Twin consisting of 3 floors (includes basement) and no insulation with a total of 16 windows. When measuring my basement, the footage is 32' x 15'. If I multiply this by 3 (floors) it gives me 1,440. Would this be my total square footage? If so, what would be correct BTU Gas Furnace for a 95% ? Also, I currently have a 80% 70,000 BTU Goodman GMP075-3 gas furnace (18 yrs old) and the Heat Exchanger cracked. 2 months ago, I replaced the bad Induction Motor, which consisted of a lot of rust (moisture)! I had to replace both hot water heater and furnace exhaust pipes to Chimney and I installed a Chimney cap to ensure water does not enter Chimney and follow path of least resistance, which would be the new Induction Motor or Furnace. If I install a 95% furnace, 2 Contractors told me I need to have a Chimney 4" liner to connect to my hot water heater so the moisture does not break apart my Chimney and mortar. One Contractor showed me a picture of a badly damaged chimney and it looked like a costly fix! Is this true that I will need to install the liner right away or can I wait a few months ($$)? One Contractor said Carbon monoxide could enter home if I do not install liner when installing the 95%. What's your professional input on all of this? Being I wrote so much, reminder if I figured Square footage correctly and what is proper 95% BTU gas Furnace?

Greatly appreciated everyone!

Kev

Knowone should guess what size furnace you need just by knowing the square footage, there is a professional way to calculate the size needed,, also a 95% gas furnace shouldn`t be vented into a chimney,
95% ers vent through pcv plastic pipe and work much safer and better when the pipe is run through the outside wall to the outside.