Abstract: An air vent insert for mounting to the perimeter of a vent opening in a building structure to provide threaded mounting holes for an air vent cover. The insert includes an open frame having front and back faces, generally rectangular inner and outer perimeter edges, a spaced apart pair of elongate end members and a spaced apart pair of elongate side members extending between the end members. The inner perimeter edge of the frame defines a central opening. The frame is designed for mounting to a building structure around the periphery of an air vent opening in the building structure such that the center opening of the frame extends around the outer periphery of the air vent opening in the building structure. The frame is also designed for mounting an air vent cover thereto such that the air vent cover substantially covers the central opening.