A window frame insert for an existing window frame can comprise: a window pane comprising a thermoplastic polymer, wherein a length of the window pane is divided into a first portion and a second portion by a living hinge mechanism formed into the window pane that extends across a width of the window pane from one edge to an opposite edge such that the first portion can bend at the living hinge mechanism toward the second portion, and wherein an outer edge of the window pane removably attaches to the existing window frame, and preferably wherein the first portion and the second portion have a haze value of less than or equal to 5% as determined in accordance with ASTM D1003-13, preferably less than or equal to 2%.