Divided Lites

Published January 10, 2021
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Lake Washington Windows

A window with divided lites is a window that appears to have multiple panes of glass making up the window. There is typically some grid pattern or panel pattern.

Ways People Refer to Divide Window Lites

  • window grid inserts
  • window grid styles
  • window grid patterns
  • windows with grids
  • window grill
  • colonial grid windows
  • colonial style windows
  • lattice windows

Have you ever wondered why the majority of windows have divided lites? Instead of just an expansive piece of glass, windows have the appearance of many different sections. In a modern window, these “divisions” are actually created by grilles either on top of or in between the glass. You have to go back to the beginning of windows to learn why the divided lite is still a design element in windows.

The First “Lites”

Many hundreds of years ago, the first glass windows appeared. Prior to glass, these were just rudimentary openings. Glass allows the light to still come through but offers protection from the elements. Glass production was in its infancy. It could only be produced in pieces about the size of someone’s hand.


These glass panes then needed to be linked together to form a larger space. Muntins joined glass. With this small iteration, window appearance still holds on to the look of the first true divided lite.

Glass Production Becomes Easier and Larger

With the Industrial Revolution, glass production became easier and less expensive. This led to the production of larger pieces. At that time the window could have just been the glass and frame, but most still wanted the traditional divided lite look. There is still a large demand for this today. Look at all the windows on your street. Do most have a divided lite?

Simulated Divided Lites vs Grilles Between Glass

Today, there are two ways to achieve the divided lite.

  1. Simulated divided lites (SDL) offer the most authentic look and give the illusion of depth. SDLs are adhered permanently to both sides of the window with a narrow spacer bar within the insulating glass airspace. SDLs provide a bit more breadth in terms of options relating to shape and finishes.
  2. Grilles between the glass (GBG) are as described, between the glass. The grille pattern is completely encased in the glass. This means less maintenance, as you won’t have to clean between all dividers. GBGs are also more budget friendly.

Ultimately, the use of SDLs or GBGs is a personal preference and depends on the type of look you want for your home.

Modern Divided Lites

For those who want the divided window lite style, it is now possible to get that historical single pane look with modern window efficiency

There are 4 ways to create the divide lite look on a window.

Authentic Divided Lite (ADL). Like the name suggests, this style uses lites that are actually divided. Each pane is a separate piece of glass. The muntin bars (wood or metal that creates the grid look) acts as a pocket and holds its own piece of glass. A four panel ADL will have four pieces of glass.

authentic divided lite

Simulated Divided Lite (SDL). As this name implies the division between the glass (panels) is only simulated so it is not an actual separation. There are two panes of glass – one on the interior part of the window and one on the exterior side of the window –  and the muntin bars are permanently adhered to the glass.

simulated divided lite

Simulated Divided Lite with Spacer Bars (SDLS). Sames as the simulated divided lite style above with the addition of spacers between the glass.

simulated divided lite with bars

Grilles-Between-Glass (GBG). Between the two sheet of glass – the interior piece and the exterior piece – are the muntin bars. This gives a smoother glass look and the perceived individuated panes.

grille between glass

Potential Custom Divided Lite Styles

As you can see there are many different types of divided lite styles. They are all very different, diverse, and available for nearly any type of house style.

types of divided lite windows


What is the difference between a mullion and a muntin?

Mullion and muntin mean the same thing – a piece of wood or metal that separates, or appears to separate, panes of glass on a window.

Can you buy grids for Windows?

You can buy grids for windows to create a divided lite look. The material used to make the grids are called muntins. 

Can you remove muntins from Windows?

You cannot remove muntins from windows, they are part of the window build and are permanent.


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Written by Lake Washington Windows

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