If you are buying new windows for your home, you might come across some architectural jargon that is not familiar, such as muntins and mullions. Many homeowners use these words interchangeably, but muntins and mullions are quite different from each other. Renewal by Andersen® of Sacramento explains the difference between window muntins and mullions.

Window Muntins

Window muntins are vertical dividers that separate the glass panes in the window. It’s important to note that muntins only apply to the inner vertical pieces, while the outer pieces are called stiles and rails. Although muntins are often associated with windows, they can refer to any kind of vertical dividers such as wood panels, furniture or doors. Window muntins are generally made out of wood, but some can be made out of steel.

In earlier times, builders used muntins because they were structurally necessary. The outer walls of buildings could not support the weight of the large windows as they were being installed. To keep the exterior walls secure, muntins were added to allow for weight to be transmitted vertically.

Window Mullions

Window mullions, which also act as supporting devices, are different from muntins. Mullions are the single vertical bars that separate two sides of a single window. They often appear to create two windows where one window would be expected. Another way to differentiate them is that mullions are heavier elements that divide larger window frames.

Furthermore, window mullions serve many purposes. For instance, they can help improve ventilation in your home. Mullions divide a stationary and a movable set of windows, allowing fresh air into your home. Additionally, these elements add depth to resist wind load as well. This is especially useful to those who live in hurricane-susceptible areas.

Today, muntins and mullions fall under the more convenient term that’s used within the window industry — grilles. It is used to describe anything that divides the panes of a window. If you want to include grilles in your replacement windows, turn to Renewal by Andersen of Sacramento. Call us today at (916) 779-5800 or fill out our online contact form to schedule a consultation.