Abstract: A window insulation system includes a window installed in a wall of a house. The window includes an enclosed space defined between first and second window panes, and at least one opening located on a side of the enclosed space. An insulating material reservoir is adapted to store insulating material, and is coupled to the opening by one or more pipes. A pump system causes a first flow of air through the pipes, causing the insulating material to flow from the insulating material reservoir into the enclosed space, filling the enclosed space with insulating material. A second flow of air causes the insulating material to flow from the enclosed space to the insulating material reservoir, emptying the enclosed space of the insulating material.