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replacement windows Phoenix

Gas Fills on Replacement Windows

There is so much more to replacement windows in Phoenix, AZ than just panes of glass fitted into a frame. The insulated glazing units (IGUs) on replacement windows consist of multiple glass panes separated by spacers and sealed around the edges to create a single unit. And the stuff between the panes isn’t just air. The special filling helps improve the insulation to make windows more energy efficient. It is an inert gas, and here is what you should know about it.

What is Double or Triple Glazing?

First, how many panes of glass does the window have? Double glazing has two panes of glass with one space in between. Triple glazing has three panes with two spaces. And in areas with extreme weather, there are even windows with four panes of glass and three spaces. The extra glass helps improve efficiency but also improves security, reduces noise transfer, and blocks UV rays. Double glazing is the standard and is a great insulator for areas with mild climates.

What are Gas Fills?

During early development, double glazed windows had oxygen or a vacuum sealed between the panes of glass. Unfortunately, the glass would expand and contract with temperature changes, and the seals on these windows would wear out quickly. Today manufacturers pump special, inert gasses between the glass. The most common are argon, krypton, and xenon.


This gas is one of the most popular options to use in IGUs. It makes up about 1% of the earth’s atmosphere, making it readily available and one of the more affordable options to use for gas fills. The efficiency of argon is 67% better than normal air. It works well in windows with larger gaps between the panes.


This gas has a bit more density than argon. And pound for pound it has superior energy performance. Unfortunately, it is not as readily available as argon, which makes it more expensive. As a result, manufacturers tend to use krypton gas in windows with a thinner profile.


This gas is newer to the window market. It has better thermal performance than both argon and krypton. Again, it is not as readily available and most homeowners cannot justify the cost of xenon filled IGUs.

Advantages of Gas Fills

Noble gasses are colorless and non-toxic. They are called noble gasses because they have more density and are not as reactive as oxygen. They help increase the insulation and cut down on noise pollution. They also do not corrode the frame materials.

Disadvantages of Gas Fills

Because of pressure differences, inert gas fills will eventually dissipate over time. Windows will lose about 1% of the gas per year. And once the gas leaks out, the window no longer performs at peak efficiency.

To learn more about gas fills on replacement windows in Phoenix, AZ visit Freelite Inc. Our experts can walk you through the pros and cons of double and triple glazing, as well as which gas fills will perform best for our climate. Contact us at (602) 233-1981 or stop by 331 W. McDowell Rd., Phoenix, AZ 85003.