Abstract: A filter apparatus for use in filtering air flow through an air-conditioning or heating system. The filter apparatus comprises a frame, a filter element, and a support member for preventing deformation of the filter element due to the force of air flow thereacross. The frame has a substantially E-shaped cross-section formed by an outer side, a pair of legs, and a rib disposed between the legs such that first and second channel sections are formed. The support member is disposed in the first channel section and across a central opening through the frame such that the rib and one of the legs hold the support member in place without the necessity of attaching the support member to the frame. The filter element is disposed in the second channel section and across the central opening of the frame. The frame is formed of an extruded length of material having three notches cut therein. The material is bent adjacent to each of the notches to form three corners of the frame.