Abstract: This invention is a method, and apparatus for performing the method, wherein ordinary single-pane windows, door, and the like, can be converted to double-pane or triple-pane insulated items. The method involves trimming of caulking material, disassembling the frame of the item, partially or fully, and placing suitable spacing material around the existing pane of glass, and placing another pane of glass adjacent the spacing material, inserting a pre-formed holding member into the frame encompassing the new pane, and reassembling the frame. The same procedure is followed for triple-pane, except that additional spacing material and glass are added.