How to Install Dehumidifiers in a Wall

Determine where you want to install your wall dehumidifier. The location you choose should not interfere with any electrical, plumbing or natural gas lines.

Mark both the inside and outside of your wall with the exact location you want your humidifier drain installed. Use a carpenter’s pencil to mark the wall.

Cut a 14-by-7-inch piece of plywood out of a scrap piece of 5/8-inch plywood using a table saw. You may need to cut a larger piece out of the plywood, depending on the size dehumidifier you install. This size is for a 50-pint dehumidifier.

Mark the wall inside your home or building with a carpenter’s pencil where you want to install the drain for the dehumidifier. Use a level to make sure your shelf will sit level.

Attach two 9-by-11-inch shelf brackets to the wall using 2-inch wood screws and a cordless drill. The top of the brackets should be level with the level line you marked with the carpenter’s pencil.

Fasten the plywood shelf to the brackets with wood screws and a cordless drill. Drill the screws from the bottom of the shelf upward.

Drill a 1/4-inch pilot hole for the drain pipe on the wall inside your home or building where you marked with a carpenter’s pencil. Using a 1/2-inch drill bit, make the pilot hole bigger, increasing it to 1/2-inch in diameter.

Prepare the dehumidifier for installation by removing any wheels or casters from it. Place the humidifier in the middle of your plywood shelf.

Measure and cut the PVC pipe sections necessary for your drain pipe. Dry-fit the garden hose adapter -- that connects the dehumidifier to the drain pipe -- as well as the 90-degree elbows. The drain connection consists of a garden hose adapter from the unit to an 8-inch piece of 1/2-inch PVC pipe connected to a 12-inch piece of 1/2-inch PVC pipe by a 1/2-inch 90 degree elbow. That piece is then connected to another 12-inch piece of 1/2-inch PVC pipe by another 90-degree elbow. This piece runs through the wall to the outside of your home or building. It connects by a 90-degree elbow to a piece of PVC pipe long enough to reach the ground outside your home or building.

Swab PVC primer on the ends of the pipes and fittings with a rag. Then swab PVC glue on the ends and connect the pieces together.

Apply a bead of caulk to the pipe where it exits your home to prevent water from penetrating the hole in the wall.

Plug the dehumidifier into the nearest electrical outlet to ensure that it works properly.

Measure and cut drywall to cover the area around your humidifier to enclose it in the wall. If you are installing this unit in an existing home or building, you need to cut the appropriate area out of your wall to install the unit.