Window Mullions and Muntins: What’s the Difference?

Windows can be customized in a number of ways, from styles and hardware finish to frame color and glass type. You can even add mullions or muntins to windows if you’re so inclined. The mullions and muntins refer to the thin strips of material dividing the glass panes of windows. While they mostly serve the same purpose and even sound alike, the muntins and mullions are actually different. 

Window Mullions and Muntins: What's the Difference?

Here’s how you can tell them apart:

Muntins vs. Mullions

As mentioned above, muntins are vertical dividers that separate the glass panes of windows. It used to be difficult to install larger windows because the outer walls of early buildings couldn’t support their weight. Builders of that time got around this problem by using muntins to provide the necessary structural support. Builders divided smaller panes of glass with the muntins, and then assembled the panes together to create a single large window. Mullions also act as a supporting device to windows, but they’re mostly used to divide larger frames. This creates the illusion of two windows when there’s actually only one. 

What Are Mullions and Muntins Used for Now?

The advent of tempered plate glass has made it easier for builders to create larger windows without the structural support created by muntins and mullions. In fact, their use mostly dropped off after World War II. Today, mullions and muntins serve as a decorative element to windows. They fall under the universal term “grille” and are used to add to the design of homes and buildings with traditional architecture.

If you plan on having Renewal by Andersen® windows installed this season, you have the option to customize them with a creative grille pattern. Let our skilled design team help you explore your options and decide on the grille that best works for your new windows. Your choices include Colonial, Farmhouse, Prairie and Modified Prairie.

Get Started on Your Window Upgrade

You need not look any further than Renewal by Andersen of Atlanta for high-quality window installation and customization services. Our communication lines are always open. Give us a call today at (866) 609-5033, or fill out this contact form to request a FREE window consultation. We proudly serve homeowners in Atlanta, GA, and other areas in Fulton County.

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