How to Check Return Air Path Before HVAC Rough-In Inspection

Return air problems do not always show up during rough-in, but they can make the system feel wrong after the walls are closed. I have been on jobs where the supply side looked fine, the unit started, and one bedroom still would not balance because the return path was too tight. By then the drywall was painted and nobody wanted to talk about cutting transfer grilles. Before rough-in inspection, I…