Condensation inside a double glazed window shows that the sealed unit has failed. Somewhere a point in the edge seal of the window has lost its integrity and is allowing water to get in. This is also known as ‘misting’ or ‘misted panels’.
Condensation usually shows when a heat source such as the sun heats the window causing moisture to rise, but if left it can lead to a volume of water sitting in the base of the window between the frames, unable to escape.
When a double glazed sealed unit has broken down it will continue to let moisture in especially when there is a change in atmospheric pressure.The spacer bar which holds the panes apart have silica balls inside to soak up moisture. There are hundreds of these but once they get to the point where they are saturated, water will then enter the gap between the panes and condensation is formed.
Condensation can’t really be prevented by maintenance, it’s something that can happen to any window but it should not be a problem for at least five years after installation, most companies will offer a ten-year guarantee if not more. Doing a little research and buying good quality products will ensure a longer life for your windows and will be less likely that you will need a repair or replacement.
Luckily a sealed unit is designed to be removed therefore it can be replaced or repaired. Thermal efficiency and sound proofing will be lost as the unit condensate so its best to get help as soon as you notice.