Description
Snap-Rite 30.5" x 18.5" R-6 Foil Top Insulated Return Air Box
The Snap-Rite 305X185-3800F is a 30.5 x 18.5 inch return air box from the 3800 series, built for ceiling and wall supply outlets where the box sits in unconditioned space. The top is foil-faced duct board, so you cut the inlet hole exactly where the run lands and fasten a start collar sized for the flex duct you are using. The box is factory insulated to R-6, which keeps the cold air inside the box and helps prevent the sweating and ceiling stains you get from bare metal boots in humid attics.
Built for a clean finished opening
- Register opening: 30.5 x 18.5 inches, to match a 30.5 x 18.5 grille or register
- Outer box is about 2-5/8" larger than the register size (33.125 x 21.125 in) and about 4-3/8" deep
- 1/2" drywall flange for a tight, square finish against the ceiling or wall
- 12-hole cluster pattern for register screws, black interior so the box disappears behind the grille
- 30-gauge wrapper; duct board top accepts R-4.2, R-6 or R-8 collar insulation
Choosing the right box
Match the box to the register size first, then pick a start collar that matches your branch duct diameter. If your job calls for sealed boots or a duct leakage test, look at the gasketed 3800FG version of this size.
