Muntins and Mullions

As part of window construction, muntins and mullions are used for different purposes.

Muntins

Muntin is an age-old term used to describe spacing inside windows, doors and other building structures such as interior paneling and exterior siding. The term is even used in the design of furniture. Today we mostly refer to muntins in windows and doors as “grids“. These separations in the glass can be on the outside of the glass or in between the layers of glass. Most often we see newer windows built today with grids inside double-paned glass.

Grids

Grids in windows and doors provide a certain level of safety for fast moving children and pets. Glass especially becomes more visible with grids. Birds especially are helped with highly visible grids viewed from the outside on a bright and sunny day. In addition, grids provide a certain esthetic appeal to the overall design of a home. These attractive additions to a window can be built into the upper or lower window sash only if desired. They are available in different designs as well. The grid color matches the window frame color for a great look.

Mullions

Mullion or mull, also referred to as a “mulled†window, is the spacing that holds two or more windows together in a single unit. It is the strip of window material that runs vertically between windows most often seen in single or double hung window units. Also quite common, mulled windows are often seen with a single or double hung window on each side of a picture window. Theoretically, mulls can be installed on any set of windows. Window units can be installed with mulls at the factory or at the job site by the window installer.