Window fogging between panes — Hilversum, Noord-Holland

Condensation or a milky haze trapped between the two panes of a double- or triple-glazed window means the insulating seal has failed. Once the seal breaks, argon or krypton gas escapes and moisture-laden air enters the gap, reducing the window's insulating value by up to 50%. The foggy appearance worsens with temperature swings and humidity changes. In some cases the glass can be replaced without removing the frame (an IGU swap), but older or specialty windows may require full replacement. A handyman or window specialist can evaluate whether a defogging service, glass-only replacement, or full window swap is the most cost-effective fix.