How to Change Window Panes From Plain to 12 Sections

Measure the height and width of the windows and note their type: casement, double hung, fixed, hinged or sliding windows. Count the number of windows that you want to convert from single panes to the 12-sectioned windows.

Order your muntins, or window grilles, from a factory that will custom design partitions to fit your windows, or purchase standard grilles from a home improvement center. Decide if you want to use wood, vinyl, aluminum or fiberglass for the material and any color options.

Wash the windows with window cleaner and paper towels before installing the dividers. One large pane is much easier to clean and polish than several small ones after the installation. Polish the glass with a lint-proof rag after washing it to remove any streaks.

Snap or glue the dividers together to form individual grills for each window. Position the assembled dividers in the window to do a dry fit to make sure they are the right size.

Install the window dividers according to the manufacturer’s directions. Some glue directly to the glass, while others are tensioned between the windows' trim work. The simplest have a self-adhesive tape on the back side that glues the divider directly on the window.