What Causes Condensation Between Window Panes?
What It Means When You See Fog Between Panes Condensation on the inside of a room is usually a humidity problem, but condensation between window panes is different. Once that seal fails, humid air slips in, the insulating layer loses performance, and the window starts to fog from the inside of the unit. A window can look fine from across the room, then turn cloudy after a cold night or a humid stretch because the damaged seal is no longer holding the spacer cavity