Gas fills between window panes have shown a measurable improvement in the thermal performance of windows and patio doors.
Our windows and doors are filled with argon gas. It is inexpensive, non-toxic, clear and odorless.
Krypton gas has a higher thermal rating than argon, but it is much more expensive to produce. It is also clear, non-toxic, non-reactive and odorless.
The tradeoff is that krypton performs best in a window where the space between the glass is about 1/4 to 3/8 inch. For this reason, it is more commonly used in triple pane windows.
The atmospheric pressure can affect windows that have so little space between the glass. Tests have revealed that Krypton has a higher gas leakage rate than argon as well.
The Renewal by Andersen Fibrex composite replacement window is designed with a wider space between the panes, 1/2 inch, and that additional space plus the argon gas, Low E4 coating and Smart Sun glazing provides excellent efficiency, without the risk of seal failure.
Thanks for your question.