How to Install a Return Air Vent in the Wall

If you're installing new ductwork, you'll need to connect the return vent to your existing system. The first step is to find the return ducts. If you're only replacing an existing air vent, you can skip to step 5. 

Installing ductwork is a much bigger job than swapping out a return vent cover, so be sure you know what you're getting into before you begin. You'll also need to identify the correct ducts before you start. Some ducts pull air from the HVAC system while others return air to the system. You want to connect to the ducts that return air to your system.

Since ductwork installation usually needs to follow building codes, it's always a good idea to check in with a local duct installer before beginning work. A ductwork technician can help you understand the local requirements and provide professional guidance. Depending on your location, you may also need to get a permit from your municipality before you begin duct installation.

Decide where in the room you will place the return air vent. Typically, you'll want to place the vent on an interior wall, in line with the existing air return ducts. Whether you put the vent on the wall itself or the floor is up to you. If on the wall, the vent can be near the ceiling or lower down. 

Once you've chosen the right location, cut out a hole in the drywall for the vent using the reciprocating saw. Use a pencil to mark the edges of the vent's opening on the wall, and measure to ensure the traced area is the right size before you start cutting. 

Keep in mind that you want the vent opening to be the size of the vent, not the size of the cover. The lip of the return vent cover should rest against the wall. If you cut the hole too large, it won't stay in place.

Now for the tricky part: Installing the ductwork. Remove any insulation or other obstacles from inside the wall. Remember to consult a local duct installer and ensure that you follow code when installing the new ductwork.

If the ductwork needs to bend around a corner, use corner pieces to make the transition flow smoothly.

After installing the new ductwork, connect it to the existing return duct. Cut a hole in the existing return duct to fit in the attachment, known as a duct takeoff. The takeoff is a connecting piece that joins the existing and new ductwork.

Use a circle saw attachment on a power drill to cut the hole for the takeoff. Then, slip the end of the takeoff into the hole. The end should have little tabs around the perimeter. To secure the takeoff into place, push the tabs up, so they are flat against the interior wall of the existing ductwork. Paint a layer of duct sealant around the connection area to securely attach the takeoff to the existing duct.

Go back to the room where you cut the hole for the return vent and place the vent cover over the opening, lining it up so that it fully covers the holes. Use wood screws and a screwdriver to secure the vent cover to the wall.