Enter your zip to
find local pros.
Windows Resources

Glass Spotlight: Insulated Glass

Chances are, if you are exploring a window replacement or renovation project, you have probably heard the term “insulated glass” discussed often. But, what exactly is insulated glass? And what factors should you consider when deciding between insulated — also referred to as double pane — and non-insulated?

Similar to other home renovation projects, opting for insulated glass is only part of the decision-making process. Several different features and characteristics can be selected based on your needs, preferences, and budget.

Anatomy of Insulated Glass Windows

In its most basic form, an insulated glass unit, or IGU, is composed of two (or more) glass panes separated by a spacer, with air or gas filling the space between each pane. This space provides insulation from outside elements and helps your home stay warmer in the winter and cooler in the summer.

For increased insulation (and cost), a third, or even fourth, layer of glass can be installed. However, regardless of the number of panes used, the core concept is the same — glass surfaces separated from each other and filled with air or gas.

The Difference Between Gas and Air-Filled Windows

Something has to go in the space between your window panes, and while you might think it doesn’t matter, it absolutely does. Opting for air or one of several available gases will impact your window replacement project cost, the energy efficiency of the final product and the longevity of the renovation.

Air-Filled IGU

The first major decision is determining whether to use gas or air in your IGU. There are several different gas options — we’ll get to those in a moment — but first, you should explore the pros and cons of using air as your insulating feature.

When filled with air, the seals that hold your window panes in place will have a longer lifespan compared to IGUs filled with gas. While this increased lifespan is minimal, it’s certainly something to consider if you are looking for maximum longevity in your project. Air-filled IGUs also benefit from typically being the lowest-cost option when compared to gas.

However, the low cost comes at a price.

Air-filled IGUs offer the lowest insulating value amongst double pane window options. As a result, they will be amongst the lowest rated insulated windows for energy efficiency. If you are looking to maximize your monthly energy savings, or have a home that is impacted by intense heat or cold, you might want to consider gas-filled IGUs.

Gas-Filled IGU

While air-filled IGUs will offer some levels of energy efficiency, this can be enhanced by filling the space between the panes with a gas such as argon, krypton, or xenon. These gases are denser than air and thus work to reduce the amount of air infiltration coming from outside and limit the amount of heat transfer through the IGU. 

As discussed earlier, gas is more prone to escaping an IGU than air, but at a loss rate of about 1% per year, many homeowners won’t notice an impact for decades.

If you decide the boosted energy savings from gas is worth the added cost, you’ll have a few options.

Argon: The Most Cost-Effective Gas-Filled IGU

Argon is the most common gas used in double pane windows due to its affordability. While it might not offer the insulation protection of other gases, it can be combined with Low-E energy-efficient windows for added energy savings. 

Argon-insulated windows might not provide the same level of energy savings as other home renovation projects, but if you’re planning a window replacement project, it might be the most cost-effective way to reduce your carbon footprint and increase your home’s comfort.

Krypton: A High-End Solution

Krypton is more commonly used in triple-pane windows and in cases when the gap between glass panes is narrow — about 3/8 of an inch or less. Compared to argon, krypton can improve a window’s insulating value by more than 10%. However, due to its steep upfront costs, it might not net enough energy savings to be worth the upgrade. But, if your main goal is to achieve a greener home and reduce your carbon footprint, it will be a better option than argon.

Xenon: Cutting-Edge Performance

Xenon brings cutting-edge technology to window insulation, providing the highest level of performance and energy savings. This ultimate green option comes at a price though, as xenon is the most costly of the common gas insulators. Additionally, it isn’t available through all window contractors.

Despite the superior energy savings, as with krypton, it might not offer the best return on investment. Xenon is typically only recommended for homeowners hoping to achieve serious eco and green energy goals — such as a LEED certification.

Planning Your Window Renovation Project

Considering what substance is between your home’s window panes might not be on the top of your renovation concerns, but that doesn’t make it any less of a decision to make. When aiming to reduce your energy consumption and carbon footprint, small decisions such as this add up quickly in boosting your home’s energy efficiency.

Contact the trusted professionals at Modernize today to connect with a window contractor in your area, and discuss the benefits and options to consider when installing insulated windows.

Find today's best prices for your
home improvement project.