Condensing furnac vent: 4' through roof or 20' through gable?
I'm working with contractor to install a new 96% efficient furnace. One of his recommendations seemed odd. When I told him I'd like him to do the roof penetration, he said "we won't mess with the roof, we'll bring it out through the gable."
Well, the roof is 4' above the ports, and the gable is about 20 feet away. Are roof penetrations really that troublesome? A-frame, typical tar shingles with embedded grit.