I don’t see a lot of HE furnaces in the tract homes around here, but most have an intake in the attic and exhaust through the roof or the intake as a downward ‘J’ at the roof near the vertical exhaust vent.
This one was a 2015 Carrier 59SP5A with intake and exhaust together vented to the exterior. Appeared to be an aftermarket ‘diversitech’ style or concentric vent kit. I wasn’t able to find in the furnace installation manual where these vents were acceptable or not. Any insight on this installation?