For most homeowners, a window is either working or broken—open, shut, or cracked. But there’s a quieter, more insidious failure that hides in plain sight: .
When the hermetic seal around an insulated glass unit (IGU) fails, you don’t get a draft you can feel or a lock you can’t turn. Instead, you get condensation trapped inside the glass, higher energy bills, and a slow path to permanent damage. To understand the break, you need to see inside the glass. Most windows made after 1980 are double- or triple-glazed. Two or three panes of glass are separated by a spacer—often filled with desiccant (a drying agent)—and sealed around the edges. The air gap is usually filled with an inert gas like argon or krypton, which insulates far better than plain air. window seal broken
That faint fog between your double-pane windows isn’t a design feature. It’s a warning sign. For most homeowners, a window is either working