Would you know why insulated window glazing looses its seal?
An insulated glass unit may fail for the following reasons:
(1) It was an older and inferior product. (Newer units are built to much better standards.)
(2) It was not properly installed.
(3) It was damaged.
Unfortunately, once it has failed, there are only two options. The first is to live with a cloudy looking piece of glass. The second option is to replace the glass with a new unit. Repairs are not possible.
By the way, the insulation value of a failed unit is not much lower than that of a complete unit. George