Desiccant
The drying agent packed inside the spacer of a sealed glass unit, there to absorb any trace moisture and keep the gap clear.
What it means for you
It explains foggy windows. While the seal holds, the desiccant keeps the space dry; once the seal fails, it saturates and you get that permanent haze between the panes you can't wipe away.
Where you'll see it
Never visible — it's sealed in the spacer. You only meet it, indirectly, when a unit fogs.
Related terms
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