External Grilles and Roof Vents

External grilles, wall terminals, cowls and roof vents — the points where your system meets the weather. Intake and exhaust terminals for wall and roof, in a range of diameters and finishes.

Two things matter more than looks here. Keep intake and exhaust far enough apart that you are not drawing your own exhaust back in, and check the free area of the grille rather than its nominal diameter — a fine mesh on a 125mm terminal can throttle a run that was sized correctly everywhere else.

Insulate the duct on both terminal runs. Anything carrying cold air through a warm roof void will sweat if you don't.