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Q&A: Is it a worth the extra cost to buy windows filled with argon gas?

Q&A: Is it a worth the extra cost to buy windows filled with argon gas?
Consumer Reports News: October 20, 2008 09:33 AM
The replacement windows I'm considering buying come with the option of using argon gas to boost their energy efficiency. Should I spend more to get the argon gas?

It is generally not a good investment to replace windows just for energy-efficiency purposes. But if you need to replace irreparable windows or are undertaking a home remodel, then consider the incremental costs of higher-efficiency replacement windows over models without such features as specialty gas fills, including argon, or low-e coatings.

Large incremental costs for these options generally outweigh their benefit. Argon, for instance, typically increases the insulating R-value of a window by only half a point. (Insulated-glass windows, also called double-pane glass, typically have an R-value of around 2.0 to 3.0. R-value is the measurement of thermal resistance; the higher the number, the more efficient the window. Learn more about the energy performance of windows.)

This small increase in insulating value from the argon gas will get you slight energy savings, but the additional initial cost could significantly extend the payback time for the windows. What's more, the argon does little or nothing to reduce transmission of ultraviolet and infrared radiation. UV light from the sun can damage your furnishings but, more important, infrared radiation transfers heat into or out of a home. Studies have shown that windows with a low-e coating can measurably reduce solar heat gain during cooling season (assuming you do not draw curtains or blinds anyway). However, homes in cold climates tend not to see a benefit from this option.

It's worth noting that many manufacturers of high-quality windows, including all those we tested for our latest report on windows, now use argon-filled glass as the standard for their windows. In fact, some companies might charge you more if you want windows with glass that provides less insulation, including models with only air-filled glass or with no low-e coating.