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The Daily Insight

Are muntins and mullions the same?

Author

William Smith

Updated on March 30, 2026

Fundamentally, muntins are the vertical shafts of wood separating panes of glass in a traditional multi-pane glass composition. Mullions, on the other hand, are the single vertical props used in two-pane assemblies.

What are mullions in a window?

A mullion refers to the vertical piece of wood separating the panes of glass, not both the verticals and the horizontal stile pieces. Today, mullions are the vertical bars between the panes of glass in a window.

Why do windows have mullions?

Well, mullions are vertical elements that divide two or more units of the windows. Their primary purpose is rigid support to the glazing of the window, but you can use them as a decoration, as well.

Are window muntins necessary?

Grids in Modern Homes Windows without grids are a little easier to clean, and they can preserve your home’s viewable light space. While grids can be excellent modern home inclusions, you might be better off without them.

Can you remove mullions from windows?

Whether you want to replace a pane of glass or you want to change the look of your French doors, you can remove the mullions relatively easily, although there is a risk of breaking the glass.

Can you remove grid from windows?

Glued vinyl grilles and grilles inside two panes of glass can’t be removed. You might want to remove the grilles to clean them or change the appearance of the window. The most common window-grille installation simply uses a frame retainer on the inside of the window.

Should I remove window grids?

Other than being hard to clean if they’re on the outside of the window, the other major complaint with grids is that they can obstruct a view. If you have a picture window looking out onto a gorgeous view in your back yard, you might want to leave off the grids.

What is a mullion in a window?

Two separate windows that are closely mated can even have that thin separating element referred to as a mullion, even though it is technically part of the wall. In the truest sense, muntins are the vertical pieces of wood separating panes of glass in a classic multi-pane glass assembly.

What are muntin and Mullion panes?

In the truest sense, muntins are the vertical pieces of wood separating panes of glass in a classic multi-pane glass assembly. Mullions are the single vertical supports used in two-pane assemblies. Grilles: Alternative to Muntin and Mullion Terminology

What is the difference between muntins and panes of glass?

It has nothing to do with the interior panes of glass. It holds the window as a whole. On the other hand, muntins have everything to do with the panes of glass. Muntins are the very narrow strips of wood that divide up the individual panes within a sash (sometimes referred to as lights or lites).

What are muntins in Windows?

Muntins are the very narrow strips of wood that divide up the individual panes within a sash (sometimes referred to as lights or lites). However, not all windows with individual panes have a wooden piece that divides them.