Double or insulating glass can leak. This is annoying, as it greatly reduces the insulation value and reduces visibility. A leak in double-glazing occurs because the frame that holds the two panes of glass together is no longer airtight. Due to the pressure difference, moist outside air is drawn in. The desiccant between the glass panes becomes saturated with moisture and condensation occurs. The dirt that comes along with the condensation can also cause stains in the cavity (the space between the glass panes).
You can recognize leaky double-glazing as follows:
The moisture or condensation is particularly visible in the morning and evening, as that is when the greatest changes in temperature and humidity occur.
Unfortunately, this is not possible. Once your double glazing leaks it is not repairable. With double glazing, the cavity is filled with dry air (old double glazing) or a noble gas such as argon or krypton (HR+ glass and above). Once this leaks out, the pane no longer insulates. The glass must be replaced in this case. Pay close attention to whether the frame is not affected by the moisture, otherwise it is wise to replace the frame as well.
