Condensation
The formation of water droplets on window surfaces when the glass temperature drops below the dew point of the surrounding air.
Window condensation is a common concern for Canadian homeowners, especially in winter. Interior condensation on the room-side glass surface indicates either high indoor humidity or poor window performance (high U-value). Condensation between the panes indicates sealed unit failure.
Exterior condensation (on the outside surface) is actually a sign of good window performance — it means the Low-E coating is preventing heat from reaching the outer pane. Managing interior condensation involves controlling humidity (target 30-40% RH in winter) and ensuring adequate air circulation at window surfaces.