Abstract: An inexpensive fresh air intake pre-filtering device for make-up air is disclosed for use with a circulating forced air heating system that is installed on an outside wall of a building. The device is comprised of a polyethylene material with an outer flange for securing the fresh air intake to the exterior wall surface. The fresh air intake housing is structured to include an aluminum frame, two sided raised pattern grill of a RX Poly-Med filter medium, manufactured from 100% synthetic fibers. This is to prevent vermin, insects, pollens, and other pollutants from passing through, while permitting the 10% of air flow required by the Nation and Regional Building Codes for residential housing. This washable filter is easily removed or installed by the pull-tab on the front of the vent housing. This Pre-filtering device is designed to prevent snow and rain from entering the fresh air intake duct.

Abstract: The fresh air intake is made of galvanized metal with a metal screen that has ¼″ open squares.