Abstract: An apparatus for winterizing a vent opening in a crawl space of a foundation in a building. The apparatus comprises a first member having each a first predetermined size and a first predetermined shape and formed of a first predetermined material for sealing against an inside surface of a wall area immediately adjacent such vent opening. A cover member has each of a second predetermined size and a second predetermined shape and formed of a second predetermined material, the cover member is secured on a first side thereof to a first side of said first member. A thermal insulating layer is engageable with a second side of the first member for providing a weather barrier to cold air and pinch handles are disposed on the cover member for assisting in positioning the apparatus in such vent opening.