If you come out one side of the house with exhaust and another with intake, some of these sealed combustion furnaces can be in trouble. It may vary, some newer furnaces are allowing vent through the roof, intake from the attic for example. I have seen some instances of intake and exhaust coming from different sides of a house. Rare but its done. 267 Every two pipe system I installed were in the same location.
Every manufacture lists installation methods with the equipment.
I did not know the reason, but they all seem to be together. Good question, I'll have to look into this further. Elbows, length of pipe, distance from openings, vents, etc., seem what the manufactures stress on this installation. All of their other models must have the pipes terminate next to one another. Any registered user or guest.