Abstract: The invention includes an extruded retainer member which is permanently affixed to the casing of an existing window and which has a ridge running its length onto which is snapped the channel of an extruded frame member, Forming a weather-tight seal. The frame member has an additional slot for securing window glazing within the frame. The ridge on the retainer member has a neck, a bulb and a tip. The channel on the frame member is formed by two flanges which are flexible to an extent and shaped so as to snap over the bulb on the ridge. A gap between the ends of the flanges forming the channel and the neck on the ridge allows the frame member to pivot relative to the retainer member. Since the tip of the ridge on the retainer member will contact the inner surface of the channel in the frame member, the amount of pivoting is restricted.

Abstract: A storm window assembly is described including a retainer member which has a ridge along its length and is permanently affixed to an existing window casing and a frame member which has a channel for glazing and a channel for snap-accepting the ridge on the retainer member and a cover frame. The frame member can pivot relative to the retainer member to allow mounting on non-vertical casings. The ridge on the retainer member has a tip thereon to restrict the amount of pivoting permitted between the frame member and retainer member.