A muntin is a strip that separates panes of glass in a window. This is commonly found in older homes whose windows were made before the 20th century. During this time, it was impossible to create large sheets of glass, so smaller panes were held together by these muntins. In today’s world, muntins are created by sandwiching thin strips of plastic or aluminum between double-paned glass or placing them on the outside of the glass for even more strength.
Oftentimes, muntins are used as a decorative means in today’s homes rather than a necessary feature found in older, historic homes. Also, there are now single-piece, removable muntins that are made from wood and snap over single large pieces of glass on the interior of the window which makes it look like smaller pieces of glass.
Muntins are also known as sash bars, glazing bars or muntin bars. They can be found in doors and furniture as well as windows. Double and triple layer insulated glass can be used to replace single panes in windows that use muntins, which reduces the effectiveness of insulation, but gives a distinct look. A professional home inspector can examine the windows of a home to determine if any repair needs to be done to existing muntins or if windows need to be replaced for better energy efficiency.