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Complete Window Grids Guide

Window grids, or window grilles, often appear in homes to add architectural interest. They can also maintain the continuity of a home’s style. A lot of terms get used to describe window grids. Here’s a handy window grids guide to help you make the best choice for your home.

Window Grid Terminology

When it comes to window grids there are several terms to describe them. The terms are often used interchangeably. Window grids are also known as grilles, dividers, muntins, or mullions.

In the past, mullions used to support window glass pieces in single-pane windows. Now they serve decorative purposes. 

Muntins also refer to the bars or dividers that form the decorative grille pattern of a window or door. Grilles specifically refer to muntins fastened to the interior side of a window sash.

Grids in windows are also called grilles. Muntins, also known as dividers or bars, create the grids and grilles.

Common Window Grid Terms

There are many terms and synonyms with different types of window grids. It’s a good idea to familiarize yourself with the various terms before you get started on a window or door replacement project.

= available in Marvin Replacement products

Marvin Replacement Window Grille Types

Marvin Replacement offers two types of window grilles: Simulated Divided Lites and Grilles-Between-the-Glass. There are many types of custom patterns you can build with those grilles. The difference between Simulated Divided Lites and Grilles-Between-the-Glass is the location of the bars.

Cutaway of a Marvin Replacement window with Simulated Divided Lites.

Simulated Divided Lite

Simulated Divided Lites have bars permanently attached to the outside surface of the glass to form grids. The grids mimic traditional looks and can form symmetrical patterns. Simulated Divided Lites can increase the appeal of a house by adding visual interest.

Marvin Replacement Grilles Between the Glass


Grilles-Between the Glass can also create grids. They differ from Simulated Divided Lites because the bars sit between the panes of glass. GBGs offer easier window cleaning because you don't have to work around the muntins, like with Simulated Divided Lites.

Window Grille Patterns

Rectangular Grille Patterns

Prairie style homes feature window grids that divide the window into unequal sizes. The grille runs near the perimeter of the window and creates architectural appeal.

Prairie style grids can have four, six, or nine unequal rectangles or panes. The lines of Prairie style grids create a sense of a prairie landscape. Craftsman and Farmhouse style homes often feature Prairie grille styles.  

A simulated check rail appears on casement windows to look like a double hung or single hung window.

Selected: Traditional

A white Marvin Replacement Double Hung window with a standard divided lite pattern.
Marvin Replacement Casement Windows with Prairie Two-Wide Divided Lites.
Image of two white Marvin Replacement Casement windows with a Prairie Two-Wide Six-Lite divided lite style.
A white Marvin Replacement Casement window with a prairie nine lite style.
Image of a white Marvin Replacement Casement window with Cottage style divided lites.
Image of a white Marvin Replacement Casement window with a simulated check rail to mimic a double hung window look.
A white Marvin Replacement Double Hung window with a standard divided lite pattern.

Round Grille Patterns

Round grille patterns feature spokes and hubs to make them unique. Our circle window can have six spokes while our round top windows can have three. Hubs can appear open or solid.

Selected: Circle Dual Hub Six Spokes

Circle Dual Hub Six Spokes
Marvin Replacement Half-Round Spoke Lites
Marvin Replacement Half-Round-Open-Hub
Marvin Replacement Half-Round-Solid-Hub
Marvin Replacement Round Top Equal-Rectangular
Marvin Replacement Quarter-Round-Open-Hub
Circle Dual Hub Six Spokes

Home Styles that Use Grille Patterns

Grille patterns are often used to preserve the historic aspects of a home’s style. They can also maintain a consistent look. Many of the grille styles include Prairie in the name as in Prairie style homes.

Frequently Asked Questions

Why do people put grids in windows?

Grids used to hold individual panes of glass in place in single pane windows. They became a characteristic look for that home style. Today, grids serve decorative purposes to add appeal to your home.

Are window grids outdated?

Window grilles aren’t outdated. They appear in many home styles and have found new popularity with Farmhouse style homes.

How to replace window grids?

Marvin Replacement Simulated Divided Lites get permanently adhered to the outside surface of the glass. Our Grilles-Between-the-Glass window grids rest between window panes. If you’re interested in replacing window grids, it’s best to schedule a service appointment with Marvin Replacement.

What are window grilles?

Window grilles are decorative bars that get attached to a window. The bars divide the window into separate sections. Window grilles complement home styles.

What are grids in windows called?

Grids in windows are also called grilles, dividers, muntins, or mullions. They refer to the bars on windows that divide the window into different spaces. Some window grids separate a window in equal proportions. Others create different shaped rectangles near the perimeter of the window.

Can you remove window grids between glass?

If you want to remove window grids between glass, it’s best for a professional to do so. Removing window grids between glass on double-pane windows poses challenges that only professionals can handle. Trying to remove window grids between glass can lead to damaging your windows and compromising their energy efficiency if you break the seal between the glass.

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