Abstract: A double window construction and particularly an interior storm window construction wherein the framing or frame of the storm window is uniquely configured to provide both window support for the storm windows installed and also a smooth interior finish relative to the window opening being accommodated. The windows themselves are chamfered at their outer edges to provide for ease of installation in tracks or channels formed by resilient ribs. The sides of each rectangular storm window, as to the frame, are generally L-configured in transverse cross-section and include outwardly facing support ribs for providing support as well as space to receive a settable fluid substance such as silicone rubber, whereby to provide a secure support for the frame. The inner edges of the frame sides are preferably cut at the job site to abut directly the interior surface of the existing window frame.