How To Repair A Pane Of Glass In A Double Pane Window

The sound of breaking glass can come for any number of reasons from your daughter's backyard baseball practice to a falling tree branch during a storm. In addition to broken glass, other reasons you might want to replace the glass in your window include scratches on the outside or even cracks in a window pane. But if you have double pane windows, can you replace the glass, or do you have to replace the entire window unit?

While that may seem like a simple question, the answer can be more complex, depending on the age of your windows, what kind of shape they are in, and what kind of Insulated Glass Unit you have. Here is some information to help you decide.

What is an Insulated Glass Unit?

First, double-paned windows are contained in an insulated glass unit or IGU. The parts of the window work together to keep hot and cold out of your home, and heated and air-conditioned air inside. An insulated glass unit is made up of several parts.

All windows have some parts in common, including a head, frame, jamb, and sill, and these are generally pretty familiar to most people.

The head is at the top. The frame surrounds the window
The sill is at the bottom.
The Jamb makes up the sides of the window frame.
The sash is the part of the frame that holds the glass.

Certain types of windows have other parts, essentially depending on whether they open or not, or how they open. The difference with an insulated glass unit and a single pane window is the sash and the glass itself. By definition, an insulated glass unit↗ is made up of two or more panes of glass, spacer material of some sort (so the panes don't simply fall together in the frame). These are sealed together at the edge.

Often, a gas such as argon is injected between the frames. These gas, which are heavier than air, help keep heat from transferring through the pane to the inside or outside of your home. What does all this mean for replacing a broken glass pane in a window?

Can You Replace Glass in a Double Pane Window?

The answer to this question is technically yes. You can, but it may not be the best idea. You can lose some significant energy savings by doing so, and your window can even be damaged in the process. Here's why:

It is possible to cause further damage to the sash and the window itself when replacing a single pane in a double-paned window↗.
Seals can be damaged during the replacement process, resulting in less efficient windows and even fogging between the panes.
Any gas injected between the panes to make them more efficient and effective will escape, again reducing efficiency.

So is there ever a time when replacing the panes makes sense? The answer is "it depends." If you have historic window frames you are trying to preserve, your frames are new or in great shape, and if the glass can be replaced without further damaging the window, it is possible. You'll want to contact a professional to be sure.

Which is the better option? Glass Replacement vs. Window Replacement

So how do you decide if you should completely replace your window or just the glass? Here are some simple questions to ask yourself and things to understand.

Replacing just the glass can be a temporary and more affordable solution until you can replace the entire window (but you'll spend more in the long run by doing both).
How old are your windows and frames? Are they relatively new, or five or more years old?
How good of shape are your frames in? Are there any visible signs of damage?
Are your windows fogging between the panes? This can be a sign that seals are already failing and you have hidden issues that may need to be addressed.
Is the loss of efficiency worth the cost savings of replacement?
Have you consulted a professional glass company about your options?

In general, window replacement is a much better idea than simply replacing the glass. It's safer, preserves the efficiency of your windows, and in the long run, will be more cost-effective. In most cases, replacing just the glass is a temporary fix at best.

It's our recommendation that homeowners replace the full window unit rather than just the glass itself. If you have questions be sure to contact a local professional.