While you're at it, you can reduce the bulk with a slimmer model. Just follow these instructions.
Cut away old ductwork to clear the way for a more compact heating-vent cover with this simple project.
Materials and Tools:
1. Remove the old vent. If the screws have been painted over, use an awl to dig out the paint and clear out the screw head.
2. If the ductwork extends out from the wall, you'll need to cut it away if you're installing a flush-mount vent cover. Protect the wall around the vent by taping it over with painter's tape, and then cut away excess ductwork with lineman's pliers. Wear safety glasses and heavy work gloves while cutting away the ductwork.
3. Remove the painter's tape and fit the new vent cover. Make sure the louvers face down.
4. Slide the vent cover into position and secure with screws. Use the awl to make a hole for starting the screw, and then pre-drill pilot holes. Start the screws by hand and then use a screwdriver to lock the vent down tight. Test the vent to make sure it operates properly.
5. If desired, run a bead of caulk along the perimeter of the frame to seal it.