How to Install an Insulated Pet Door

Remove the door from its hinges and place it on a raised workplace, such as two saw horses. While you'll install the pet door on the bottom of the door, you can center it at the bottom or off-center as necessary. Mark the height of your pet on the door, leaving 3 inches from the bottom of the door to the bottom of the hole to cut.

Tape the template into place. With a drill and 3/8-inch drill bit, drill holes on each of the four corners of the template. Using a table saw, cut along the template line, beginning from one hole. Once you finish cutting, remove the cut-out piece, and clean your door of the tape and the excesses of the template.

Measure the thickness of your door and add 1 inch to it. Measure and cut the tunnel pieces (included in the kit) according to the measurement you calculated, noting not to cut the grooved side. Slide the weather stripping pieces into the side of the tunnel and cut them to size. Using a pair of scissors, cut along the groove for each tunnel. Snap each tunnel piece into the door so that they are facing out and down. The tunnel pieces should fit squarely on the pet door. Tape each corner.

Place the pet door on the interior side of your door and align it. Drill holes along the edges as indicated and place the exterior frame on the exterior side of your door. Aligning the two portions so that the holes coincide, insert one of the screws provided through both frames, and secure the other side of the screw with the matching nut from the kit. Repeat the process with the remaining screws to secure the pet door. Flip your door over and cut away the excess length of protruding screws with a bolt cutter. Remount your door.