Gas-filled windows boost efficiency and comfort and also save you money. 

One of the common questions window shoppers ask is: “Are gas-filled windows worth it?” Here’s a quick answer followed by a quick explanation: YES! 

gas filled windowsDouble-pane windows are more efficient when the thin space between them is filled with either argon or krypton. They are safe and non-toxic and also denser than air. That means less hot air from outside can pass through a window and into your home if you live in a hot climate. And in a cold climate, it means less warm air from inside your home – the kind you want to keep in – can escape through the window.  

The result is a more comfortable home, thanks to stable temperatures and fewer drafts. It also means less reliance on heating and cooling systems, and that can lead to lower monthly utility bills. In most instances, the savings can offset the higher price tag of windows with gas fills, lowering your overall cost over time – especially if you claim the many rebates and tax incentives available.  

Argon is less dense and less expensive and is considered one of the most common window insulation gases today. On the other hand, krypton is six times denser than argon and twelve times denser than air.  This makes it more expensive but also more effective. Window manufacturers often blend some of both gases in the most efficient windows, which balances elite performance and affordability.  

The best windows filled with gas are efficient for other reasons, too, such as the materials they’re made from. Not only do gas fills make a window efficient, but they are a core ingredient. If you’re unsure whether your windows have gas inside them, well, if they are good ones, then they probably do.  

According to the International Association of Certified Home Inspectors, you may be able to tell whether a building’s windows are gas-filled by checking the specifications on the window tag, which is typically found along the bottom inside track of the window. There also could be two small holes along the spacer – one where the gas entered the unit and the other for air to exit. Read this recent blog if you’re unsure where the spacer is on a window 

One factor to remember is that no window is completely sealed – there is always some air leakage. That goes for gas fills too, but this is not a problem. According to the National Renewable Energy Laboratory, argon and krypton are safe and non-toxic, and the leaks are tiny – about 0.5% of total gas might leak per year. So even a 20-year-old window, nearing the end of its lifespan, would still perform at 90% of its original capacity. In inefficient windows, however, larger gas leaks present no health risks but can be significant enough to cause condensation.   

For more information on gas fills and other parts of an efficient window, head to our site’s Types and Parts section for a fast tour. And use the Window Selection Tool to see a list of gas-filled windows right for your climate and home.