What Are Gas-Filled Windows?

Gas-filled windows are made as an option in virtually any new window purchase these days and they’ve earned that popularity for many reasons, mainly because of how energy efficient they are. Gas-filled windows are either double- or triple-paned glass windows, with the space between the glass filled with a dense, inert gas. This creates an insulating layer that improves the thermal properties of the windows. Some other benefits of gas-filled windows are listed below:


    • Condensation and frost reduction: Gas fills enhance the heat insulating properties of windows during the winter and keeps the inner pane of glass at a warmer temperature, meaning that there will be less condensation on the windows when the outdoors temperature drops. This subsequently helps with the prevention of mold formation inside the house, as mold only thrives when there’s enough built-up humidity to sustain it.
    • Soundproofing: Due to the density of the gases that are typically used for gas fills, sound transfer through the windows is significantly reduced, which will keep your house sheltered from any noise coming from outside.
    • Versatility: Gas-filled windows can be used in all climates, and maintain their insulating properties no matter what the conditions are. In the summer, they prevent heat from entering your house, and in the winter, they prevent heat from escaping.


  • Stability throughout the seasons: All gases used in gas-filled windows are extremely stable and do not expand or contract when exposed to high or low temperatures. This prolongs the life of the window by preventing distortions of the window frame that can be caused by changes in the pressure of the gas filling.


  • Cost-friendliness: The most common gas-filled windows are only $40-$50 more expensive than their normal counterparts. For the benefits you get, it’s a reasonable investment.


Types of Gas-Filled Windows:

The main difference between the different types of gas-filled windows is in the gas that’s used to fill the space between the glass panes. All gases that are used are dense and inert. Below is a list of commonly used gasses:

  • Argon: Is the most commonly used insulating gas in windows due to its balance between being an excellent insulator while maintaining budget-friendly prices.
  • Krypton: Is denser than argon, but comes with a heftier price tag; it’s increased density allows the space between the panels of glass to be reduced.
  • Xenon: Is denser than krypton, but isn’t used as much as argon and krypton due to its price; is sometimes combined with argon and krypton.


Concerns about Gas-Filled Windows

A common concern that many people might  is whether gas-filled windows will leak the gas filling or not. The short answer to that is yes: all gas-filled windows leak a small amount of their gas, but not enough to reduce the insulating properties of the windows or their typical lifespan of 15-20 years. Estimates of the amount of gas that is leaked are less than one percent per year, and a quick mathematical calculation (0.995^{20}) will tell us that after 20 years, a gas-filled window will have lost only 10% of the amount of gas it had in year 1; such a small loss will barely affect the heat insulating properties of the window. By the time this amount of gas escapes, most people will have already began thinking about replacing the windows with new ones.

Another concern that people might have is the safety of gas-filled windows, and whether the gas leaks will affect the health of the house’s inhabitants. All the gases that are used in gas-filled windows are inert, meaning that they don’t chemically react with anything, and therefore will not affect anyone’s health in any way. Furthermore, the gases that are used in gas-filled windows are already present in the atmosphere, which won’t make your house’s air any different from the one outside.


Which Type of Gas Fill is Best For You?

Argon is considered to be the best option for most people as out of the three gases that are mentioned in this article, argon gives you the best bang for your buck at around $40-50 per window. Due to argon’s economic price, some manufacturers such as Marvin offer argon-filled windows in their standard packages as a default. If you’re looking for slightly higher insulating properties though, krypton or a combination of krypton and xenon will work best for you–be aware that adding on xenon will increase the cost quite a bit though.