Customer Installation Story
Story is is provided to better educate you as the potential installer.

Here is a nice example of a 3D dryerbox install in a 2x4 wall.  The customer sent several pictures and provided a nice summary.  Because the room to the rear was a bedroom, he used a sound deadening material on the back side of the dryerbox similar to Dynamat material (actual product used was eDead 45)

His comment to me: “I have found the dryerbox and dryer-ell to be of the highest quality and utility. Thank you for your assistance with this project.”
—Dave

In-wall Duct Tips

Before—Several problems: Vent position doesn't line up with the back of the dryer; foil hose has sharp kinks and can get crushed against the wall. No gas shutoff valve present (code says must be in the same room and easily accessible). Sharp bends in the vent line inside the wall restrict flow and increase drying time. 240V electrical plug is in an inaccessible position.
Cutting away the baseboard molding between the center studs to make room for the dryerbox. Gas line has been shortened and both electrical boxes relocated. Dryerbox will be located in the center cavity so that the vent from the wall lines up with the vent in the center of the back of the dryer.

Ready to cut a new hole in the floor and install the dryerbox. Note rerouting of electrical wires. When the 240V electrical box was relocated, the 3-prong receptacle was upgraded to a grounded 4-prong receptacle.

Hole cut for new vent line. Note: I was able to cut a slightly oval hole (4.5 x 4 inches) by drilling two pilot holes side by side and then using a 4 inch hole saw to gradually bore two 4-inch holes separated only 1/2 inch center to center.

Dryerbox installed, gas line extended and gas valve installed and leak checked, and wood framing scabbed in place for ease of drywall reinstallation.

The old dryer vent line has been removed and covered over with a small piece of OSB screwed to the underside of the subfloor. The new vent line uses the 10 inch radius dryer-ell for reduced friction loss. (Removal of two sharp 90 degree bends reduces the "effective" length of the in-wall vent line from about 35 ft to the actual physical length of 25 ft.) Note: The owner's manual for my Kenmore dryer (made by Whirlpool) actually requires a 10 ft reduction in the total length of rigid duct for each sharp 90 degree bend!