Schedule a Free Consultation

Window Mullions and Muntins – What’s the Difference

When we think about the parts that make up our windows, we usually think about panes of glass, sills, frames and casings. While you may not have heard about mullions and muntins, it is quite possible that you probably already have them on your windows or even your patio doors without even realizing it. So, what are muntins and mullions?

Window Mullions and Muntins - What’s the Difference

Window Mullions

Window mullions are the vertical bars that divide two or more panes of glass in a window. Although their main purpose is to provide rigid support, they can also serve as a decorative element. Prior to the Victorian era, it was not possible to manufacture large sheets of glass, so large expanses of windows were achieved by providing them with support via the use of mullions.

Window Muntins

Window muntins, on the other hand, are sash bars made of wood or metal strips that separate and support the glass panes in a window. Muntins only refer to the inner vertical pieces. While they are most associated with windows, they can also mean any kind of vertical divider used for doors, wood panels and even furniture.

To put it simply, muntins are inner, vertical elements that separate panes of glass in a multi-pane window while mullions are single vertical supports used in multi-pane assemblies. Not many window companies make a distinction between muntins and millions because few homeowners care about this, and, oftentimes, they are used interchangeably. A more buyer-friendly term that window manufacturers use is grille.

Whether it’s French doors or your traditional casement window, you will probably see these elements in most houses in your neighborhood. If this is something you care about when looking for windows to purchase, give Renewal by Andersen® of St. Louis a call (314) 332-2364, or fill out our contact form to speak to one of our window experts.

Reviews

"Our installation team was top notch. While they said they were sending a "team"to install 21 windows it was only two people. But I see why, the process was seamless and everything was done correctly and consistently with the leadership of Clayton. We had a tiny problem with one window within a week of installation and their response time was prompt to remedy the situation. Our windows are beautiful. Our home is warm and cozy."

Eileen McKeon | St. Charles,
January, 1

"Love the windows and patio door. We want to finish the whole house when we can financially. We give Anderson and employees, especially the sales rep Mike that came to our house, the highest rating. Mike was knowledgeable and courteous. Also not high pressure."

Gail Wilson | O FALLON, MO
January, 1

View All Reviews