Condensation on double glazing can mean two very different things: an innocent consequence of humid indoor air, or a sign that something is wrong with the window itself. The difference lies in where the condensation forms.
Condensation on the inside of the glass
If you see moisture or droplets on the side of the glass facing the inside of your home, it is usually a sign that the humidity inside is too high for the temperature of the glass. Double glazing provides good insulation, but the inside of the pane is still colder than the rest of the room. Humid air that comes into contact with that colder glass condenses there faster than it would on a well-insulated wall.
Condensation between the two panes of glass
If the moisture is actually between the two panes, i.e., in the cavity of the double glazing itself, then a different problem is occurring. Double glazing uses a sealed air cavity between the panes, often filled with dry air or an inert gas. If the seal of that cavity becomes damaged, moisture can penetrate inside and remains permanently visible as a hazy, sometimes persistent mist between the panes. This does not resolve by ventilating or dehumidifying: the window itself is damaged and must be replaced.
How do you recognize the difference?
- Inside: the condensation is wet, can be touched and wiped away, and disappears after ventilating or heating.
- Between the panes: the mist remains, even after cleaning, and constantly returns to the same spot.
What does condensation on the inside mean for your home?
Condensation on the inside of double glazing is not a defect in itself, but it is a signal that the humidity in that room is on the high side. If this occurs regularly, there is a greater chance that moisture will also remain in other places in the room, such as window frames or a cold outer wall. In the long term, this can contribute to mold growth around the window.
What can you do?
Ventilate the room regularly, especially after cooking, showering, or drying laundry, and perhaps leave a window ajar if you notice that the glass is fogged up in the morning. If that does not help enough, the humidity in that room is structurally too high for the current ventilation. Our advice in that case is to use the Dynter AirPure DH251 to actively lower the moisture level so that the glass fogs up less quickly.
If condensation is visible between the panes, no device will help: in that case, contact your glazier or the supplier of your window frames, because the insulating effect of that glass has already been reduced.