Condensation in double glazing occurs when the temperature inside a room is significantly different from the temperature outside, causing the moisture in the air to condense on the cold surface of the inner pane of glass.
Double glazed windows consist of two panes of glass separated by a small gap filled with either air or an insulating gas, such as argon. This gap acts as a thermal barrier, reducing the amount of heat that can pass through the window, thereby reducing heat loss and improving energy efficiency.
However, if the temperature inside the room is higher than the outside temperature, the inner pane of glass can become cooler than the room temperature, causing moisture to condense on its surface. This is because the cold glass surface cools the warm, moist air that comes into contact with it, causing the moisture in the air to condense into droplets.
In addition, if the seal between the two panes of glass is compromised, allowing moisture to enter the gap between the panes, this can also cause condensation to form. This is because the moisture in the gap can condense on the inner surface of the outer pane of glass, or on the surface of the inner pane of glass, depending on the temperature difference between the inside and outside of the window.