The Dissipation of Argon in Windows

Function

• Argon is a clear, odorless gas that some window manufacturers use to increase the energy efficiency of multiple-pane windows. Argon doesn't transfer heat well, so it can reduce a home's heat loss in fall and winter and cut energy costs if it’s injected into the spaces between windowpanes. Argon works best when it fills a 1/2-inch space between panes, according to the Efficient Windows Collaborative.

Argon Loss

• The argon trapped between panes usually dissipates over time, even in top-quality windows. You can expect about a 10 percent loss of argon from a window over 20 years, according to "Fine Homebuilding" magazine. Nonetheless, the magazine indicates that filling windows with argon and covering panes with low emissivity coatings increases energy efficiency nearly 100 percent, when compared with the performance of standard windows with clear panes. Low-E coatings are thin, metallic layers applied to panes to control the amount of solar heat that enters a home.

Energy Efficiency

• The value of gas-filled windows is questioned by ConsumerReports.org, which notes that argon-filled windows are more expensive than standard double-pane windows. The site indicates that argon increases a window's "R" value by a mere half point without dissipation. The “R” value signifies a window's thermal resistance, and windows with higher “R” values are more energy-efficient. Double-pane windows without argon generally have an "R" value ranging from 2 to 3, according to ConsumerReports.org.

Considerations

• Argon-filled windows might be the least effective in hot climates, even before any dissipation occurs. ConsumerReports.org notes that argon does little to block ultraviolet light and reduce the transmission of radiant heat into a home, when compared with low-E coatings. UV light can fade upholstered furniture, rugs and other belongings. Unlike argon, low-E coatings can effectively block UV light and the radiant heat that drives up home cooling costs in hot climates.