Moderate Urgency
Failed Double Pane Window: What Happens and What to Do
Failed double-pane windows lose their energy efficiency and show fogging or condensation. Virginia Glass Windows explains your IGU replacement options throughout the DMV area.
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Warning Signs
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Known Causes
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Solution Steps
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Professional Assessment
Common Symptoms
Foggy or hazy appearance between the two glass panes
Condensation or water droplets trapped inside the window unit
Rattling noise from the glass unit — indicates loose glass in the spacer system
Window feels cold to the touch even with heating running
Visible bowing or distortion of the glass panes
What Causes This
Sealant failure from thermal cycling and UV exposure over 15 to 25 years
Physical damage to the glass edge or frame allowing seal breach
Manufacturing defect in the IGU assembly
Improper installation with inadequate support or over-tight fastening
How to Fix It
Solution Steps
1Verify the problem is IGU failure rather than interior condensation (wipe the surfaces — if moisture is between panes, it is IGU failure)
2Measure the existing IGU dimensions precisely — thickness, width, height, and spacer width
3Order a replacement IGU with matching specifications and gas fill
4Remove the window sash and install the new IGU with proper glazing tape and structural support
When to Call a Professional
All IGU replacement work — improper installation voids the warranty and risks future seal failure
When multiple windows need simultaneous replacement
Specialty shapes, divided lights, or impact-rated windows requiring custom IGU fabrication
Stay Ahead
Prevention Tips
Choose IGUs with 20-year or longer warranty from reputable manufacturers
Ensure proper installation with setting blocks supporting the glass weight at the corners
Avoid contact with harsh chemicals or cleaning solvents near the window perimeter
Common Questions
FAQs About This Problem
Yes — in most cases you can replace just the IGU (insulated glass unit) without replacing the entire window frame. This is significantly less expensive and is the standard repair approach for double-pane window failure.
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