Model DB-4D Specifications

Model DB-4D Close Up

Model 4D is designed for downward venting exhaust systems and floor standing dryers.

Downward Venting

Upward VentingDiagram A For 2x4 walls, add a single furring strip to each stud or use the 3 ½" deep Dryerbox Rest Dryerbox on bottom plate or on the floor.
Install as low and as near to the center of the expected dryer location as possible.
Baseboard LocationDiagram B
Caulk Void Left From RouterDiagram C
Dryerbox Model 4D Cut Sheet

Installation Instructions

  1. All standard American clothes dryers have an exhaust port in the center of the rear panel at the very bottom. Therefore, it is best to install Dryerbox® as low as possible so that the bottom tab is at or slightly below the finished floor level (not applicable if stackable unit or on a pedestal (Diagram A). The centerline mark on the Dryerbox® should be located as close to the proposed appliance center as possible.
  2. This model is for downward exhaust direction. If you are venting up, out or to the side use our original Dryerbox® Model 425 or 350.
  3. When installing the 4 ¼” deep Down-Box™ (Model 4D) into a 2x4 wall, fir out the respective wall ¾” with a 1x2 furring strip to provide adequate depth or use the 3 ½” Model 3D.
  4. When installing in an exterior frame wall, you should add insulation or duct board to the back-side of the box to minimize condensation and temperature transfer.
  5. To achieve a fire resistance rating (one-hour F & T) min. 2X6 wood or metal framing is required. The Dryerbox unit must be installed in accordance with the UL Cabinet System listing. An extra layer of type-X drywall must be installed in the ID of the stud cavity in which the Dryerbox is located. Drywall must be attached to nailers (minimum 1” X 2”) located on the inside of the cavity wall studs. Secure nailers to wall framing at max 18 in. OC. The screws used to attach the inner layer of drywall shall be spaced a maximum of 18 inches apart. For metal studs, mineral wool (min density 4 pcf) must fill the entire Dryerbox wall cavity and minimum R13 Fiberglass insulation in adjacent cells. For wood studs, mineral wool or R19 Fiberglass insulation must fill the Dryerbox cavity. Visit for more detail.
  6. Although not required, wrap the black iron gas line with vinyl tape where it penetrates or use a termination plate on the adaptor fitting of a gas line if applicable.
  7. Insert the 4” snaplock pipe about 2” through bottom port for the homeowner to connect the flex transition hose at a later time (Diagram A). Secure with silver tape, foam or caulk.
  8. Use a Roto-zip-bit router tool to cut the drywall leaving a caulk joint for the painter (Diagram B). It is best to caulk or mud this void (required for One-Hour Rating).
  9. The baseboard is best terminated with a tapered back-cut into the rim extension on either side of box (Diagram B).
  10. Exposed metal can be left unpainted or can be sprayed with an acrylic latex or oil-based (alkyd) paint when the rest of the wall, trim or baseboard is painted.

Model 4D

Recessed Dryer Vent Box - Model 425 prevent dryer lint buildup in the laundry room.
Sku DB-4D
(For Downward Exhaust Direction)
  • 22 gauge aluminized steel weighing 4.31 pounds each
  • Lower port measures 4 1/8" with very slight oval shape
  • Distance from nailing flange to rear of box is 4 1/4"
  • Overall measurements: 19" h x 16 3/4" w x 5 1/8" deep
  • Inside measures  14" wide x 16" tall
  • Five units per carton, 36 cartons per pallet, ships as a class 70