Do 3M® Window Films cause seal failure when applied to insulated (double-pane, Thermopane) windows?

No. 3M® Window Films do not cause seal failure. Millions of square feet of 3M® Window Films have been applied to insulated windows since the late 1960s, without any evidence that these films cause seal failure. 3M® solar control window films applied to the inner pane of an insulated glass window will increase absorption of solar energy and raise the temperature of the glass pane. Some of this heat will transmit to the airspace, slightly raising the airspace temperature. However, even a highly unusual 20°F increase in airspace temperature will result in an air pressure change of less than three percent. Insulated windows are designed and tested to withstand air pressure changes of up to 22 percent. The risk of insulated window seal failure is primarily a function of product quality. Cheap windows are more likely to experience seal failure. The best way to reduce this risk is to invest in quality windows from a manufacturer with an established track record building insulated windows.  more