The exhaust cools off within a very short distance......so installing piping will accomplish nothing as far as 'heating'.
It will cause back-pressure issues which will result in furnace shutting down.....resulting in NO heating.
Combustion side fan is designed to supply just enough air flow for proper combustion (fuel/air ratio). Disrupt that and no heating...problems with ignition, problems with maintaining main flame, problems with excessive heat within exchanger---high temp trip.
NO it won't work.
'4 Season' rig.....
Fill fresh water tank-use pump>>>>>>>disconnect water hose and stow (use during daytime to top off tank)
Shop light in take area......GOOD!
Ice maker line blocked off......Good!
We spent 2 weeks in temps that didn't get above 0*F and went as low as -14*F.
Propane, propane,propane......run that furnace
and open cabinet doors at night so heat can get to areas under cabinets where water lines run
