Signs of Window Seal Failure

Why This Matters

Double-pane windows rely on airtight seals. When they fail, insulation value drops dramatically.

Key Signs to Watch For

• Condensation between panes: Clearest sign — moisture entering through broken seal.
• Cloudy glass: Mineral deposits from repeated condensation.
• Visible cracks in seal: Inspect edge of glass for cracked sealant.
• Drafts: Air movement indicates seal failure.

What You Should Do

1. Check warranty — Many have 10-20 year seal warranties.

2. Consider defogging — Doesn't restore insulation.

3. Replace sash, not whole window — If frame is good, cheaper.

4. Upgrade glass — Low-E and argon when replacing.

When to Call a Professional

A window professional can assess whether sash replacement or full window replacement is needed. Multiple failed seals may justify full replacement.

The Bottom Line

Staying ahead of windows & doors maintenance saves money and prevents emergencies. Search our directory for a trusted windows & doors professional.