Model DB-425 Specifications

Model DB-425 Close Up

The 425 is the flagship model having been designed for the most common new construction dryer exhaust configuration. While there are a few exceptions, it is primarily used for venting upward in 2 X 6 walls. Where wall depth is restricted, it can be installed in a 2 X 4 wall with a 1" furring strip. The only time the 425 should be inverted is to support pedestal or stacked units for downward venting. This model was designed to allow room for other mechanical components in the cell of the wall. It is narrow enough to share plumbing or electrical runs.

To provide dryer-type flexibility (in the event that someone wishes to change from a pedestal dryer, for instance, to a floor standing dryer), select the new Model 480 for a standard installation.

Most Popular Model

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.
Duct Pipe Support TabDiagram B
Baseboard LocationDiagram B
Caulk Void Left From RouterDiagram C
Dryerbox Model 425 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 the Dryerbox® as low as possible so that the bottom tab is at or slightly below the finished floor level (Diagram A)—not applicable if stackable unit or on a pedestal.
  2. Attach Dryerbox to stud and bottom plate at a minimum of 3 corners with drywall screws.
  3. We strongly recommend that the Dryerbox be installed with the port up, although it will work lying on its side. Do not install with the port down unless the dryer is a stackable unit or on a pedestal. For downward exhaust direction use the "Down- Box™" Model 4D or 3D (more information online).
  4. When installing the 4 ¼" deep Dryerbox (Model 425) 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 350.
  5. 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.
  6. To achieve a fire resistance rating (one-hour F & T) 2X6 wood 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. The entire depth of stud cavity with Dryerbox must be filled with R19 fiberglass batt insulation. Additional insulation shall be added within the cavity as necessary to completely fill all voids around the periphery of the Dryer box and around the dryer vent pipe. Visit for more detail.
  7. Gas line termination options: For black iron pipe, wrap vinyl tape around throat where it penetrates. For corrugated stainless steel tubing, secure the CSST Termination Fitting with a Jamb nut to securely affix the termination to the receptacle. The gas port can be enlarged or relocated easily with a step bit.
  8. The new Duct Support Tab (Diagram B) in top port will assist in maintaining the ideal penetration length of the 4" Snaplock rigid conduit of 2 inches. Create a "hook" by bending the tab at the weakened or scored locations. Break-away when duct is fully supported in-place. Seal penetration with foil tape or sealant caulk.
  9. The snaplock pipe can be vented straight up to a roof jack (Diagram C), to a side-wall vent hood (Diagram D) or downwards to a crawl space or floor joist system with two elbows. The width of box and width of snaplock pipe will facilitate 16" o.c. stud spacing. Do not turn this box upside down unless stackable unit or on pedestal. Use the Model 4D or 3D to go down.
  10. Use a Roto-zip-bit router tool to cut the drywall leaving a caulk joint for the painter (Diagram E). It is best to caulk or mud this void (required for One-Hour Rating).
  11. The baseboard is best terminated with a tapered back-cut into the rim extension on either side of box (Diagram E).
  12. Exposed metal can be left unpainted or can be sprayed with an acrylic latex or oilbased (alkyd) paint when the rest of the wall, trim or baseboard is painted.

Model 425

Recessed Dryer Vent Box - Model 425 prevent dryer lint buildup in the laundry room.
Sku DB-425
(For Upward Exhaust Direction)
  • 22 gauge aluminized steel weighing 4.14 pounds each
  • Top port measures 4 1/8" with very slight oval shape
  • Distance from nailing flange to rear of box is 4 1/4"
  • Overall measurements: 21" h x 12 1/2" w x 5 1/8" deep
  • Inside measures 9 1/2" wide x 18 1/4" tall
  • Five units per carton, 36 cartons per pallet, ships class 70
Model 425 Installed and PaintedModel 425 Installed and Painted