An integrated window sash includes a sash frame having a first sheet supporting surface, a second sheet supporting surface spaced from the first sheet supporting surface, and a base between the first and second sheet supporting surfaces, the base defining an opening; a first sheet having a first major surface and an opposite second major surface with marginal edge portions of the first surface of the first sheet secured to the first sheet supporting surface, the first sheet sized to pass through the opening toward the first sheet supporting surface; a second sheet having a first major surface and an opposite second major surface with marginal edge portions of the first surface of the second sheet secured to the second sheet supporting surface, the second sheet sized to be larger than the opening, wherein the first major surface of the second sheet faces the second major surface of the first sheet and is spaced therefrom to provide a compartment between the sheets; and a retainer mounted on the base between the sheets and having a first end portion engaging surface portions of the second surface of the first sheet and an opposite second end portion secured to the base.