10 Warning Signs You Need New Windows (And What They Cost)

Windows don't fail catastrophically like a furnace or water heater. Instead, they degrade gradually — becoming less efficient, less secure, and less comfortable over years. The challenge is knowing when "aging" crosses into "needs replacement." This diagnostic guide covers the 10 most reliable warning signs, what causes each problem, and what it costs to fix.

The average window lasts 20–30 years, but climate, material quality, and maintenance can shorten that to 15 years or extend it beyond 40. Knowing the signals helps you plan replacement on your timeline — not during an emergency.

Foggy windows with moisture trapped between the panes indicate a failed seal. Once the inert gas (argon or krypton) escapes and humid air enters, the insulating value drops by 30–50%. This is irreversible — you can't reseal an IGU (insulated glass unit) effectively.