Determine what size vent cover is needed. Remove the existing vent cover by unscrewing the two attaching screws with a screwdriver.
Measure the inside opening of the ventilation duct with a tape measure. Sometimes the vent ducts are not cut properly or to a universal size. For this reason it is a good idea to measure the existing cover as well. Be sure to measure the part of the cover that inserts into the ventilation duct.
Inspect the ventilation duct for dust and debris. Use a vacuum cleaner to clean out the ventilation duct as necessary. Run the hose of the vacuum into the duct work as far as possible to remove dust.
Inspect the holes that the attaching screws were in. It may be necessary to insert plastic anchors into them. This will ensure that your new vent is installed securely. Avoid using larger attaching screws if possible. If larger screws must be used be sure that you drill the new vent cover holes to the size of the screw. This will ensure that your new vent is installed securely.
Install the new vent cover into the ventilation duct. Make sure that it fits all the way around the perimeter and it is meeting the floor.
Attach it with the two mounting screws. Make sure they are snug but not over tightened.