Defective Window Coating ?

[wedgren]

I do not have any pictures , but I have seen several Low E windows that have grey/ black dots and streaking between the panes . It appears that the low e coating has become visible . I searched on this topic , but didn't find much . Have any others noticed this , and any ideas as to the cause ?

Another thing to write up I guess !

[Robert Jones]

Sounds like a case of a failed seal, especially if the streaking is between the panes.

[Tom Raymond]

There's basically two types of low e coatings; a hard coat that is embedded in the glass, and a soft coat that is molecule thick layers applied on the surface of the glass. Soft coat low e is fragile, and when moisture enters the airspace the metals corrode creating spots and streaks that at first glance look almost like mildew.

It's broken and needs to be replaced.

[Rick Bunzel]

It really doesn't matter whether its failed coating or moisture between the panes. The glass has failed and needs replacement. At least this type of failure is easier to spot!

//Rick