Thermal Pane Water Leak

Seal Leak

• The seal around the thermal pane may eventually fail, typically on the outside where the pane is subject to weather conditions. When this occurs, water vapor seeps in between the glass panes. This water vapor, faced with two frequently different temperatures from inside and outside the house, often condenses. This forms a mist or fog on the inside of the panes, the telltale sign that a leak has occurred.

Effects

• If the thermal pane was filled with air before the leak and the seal remains in place on the house-side of the window, it can still help prevent thermal transfer. A small leak that allows water vapor will not have a large impact on thermal transfer. For versions with inert gas, thermal resistance will be impacted more as the gas leaks out. The primary issue is the appearance of the fogged up pane.

Solution

• There is no long-term solution for fixing a leaking thermal pane. You could try to reseal the pane along the edges where it failed, but the moisture will still be trapped between the panes. The best solution is to fully replace the window, an expensive option that may only be practical if a high amount of moisture is trapped or if the windows are old and need replacement anyway.

Framework

• When inspecting a thermal pane leak, pay attention to the window framework, as well as the window itself. Some window frames, including wood and vinyl, may warp and allow the window to be damaged more easily by weather, potentially creating cracks for moisture to enter. Fixing the frame can prevent the problem from occurring again.