What are these weird specks inside our window?

Hi gang! Apologies, I’m not a window cleaner, just a civilian, but you seem to have the best forum for weird window issues on the Internet :laughing:

We renovated our bathroom about six months ago and had a new window installed. It’s double paned, pretty standard as far as I know. We’ve just noticed that there is some weird speckling on the inside of the exterior pane - not sure if the photo really captures it. Any thoughts from anyone on what could cause this? Many thanks in advance.


“inside of the exterior pane” makes me think it’s in-between your double pane, correct?

If so, my opinion would be a cracked seal. Moisture gets it, especially with high moisture involved with bathrooms, the sun hits it, the moisture drys and leaves hard water deposits on the pane. (And/or messes with any tinting or treatment used in between the panes.)

Looks kinda like Low-E delamination.
Is it a mirror or a window?
Usually don’t see that on mirrors ( sometimes on older or repurposed glass).
The pattern looks linear and somewhat consistent…likely a fabricating issue with one of the glass panes.

Yep, in-between the double pane. I tried cleaning both sides of the window just to check!

Thanks for the input. A cracked seal doesn’t sound like something that should happen within six months of installation, right?

Yep, it’s a window. Thanks for the input - another possible cause that suggests a bad quality window!

Probably not a cracked seal, more like a factory defect of the coating in between.
I have seen this many times on new houses.
Either way it should be covered by warranty.