A failed insulating seal. The window still functions and the failure is cosmetic plus a modest efficiency loss. Glass-only replacement is sometimes possible and much cheaper than the full unit.

You can handle this one yourself. No call needed.

Related

• Condensation on the inside in winter
• Sash that will not stay up
• Drafts at the frame rather than the sash
• Rotted wood sill under an older window
• Original single-pane aluminum
• Hail damage to window frames and screens
• Broken thermal seal still under warranty

Back to Windows.

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Written by Jaylan Jones. I Like To Exterior Services earns a referral fee when a call connects to a contractor. See our business-model disclosure.