06/18/2026
Fascinating example of myths and fables substituting reality, as far as building science is concerned. There are over 100 comments, some of which allege professional knowledge and experience, of which none is correct. If you want to list some of the many things wrong here, go ahead. https://www.facebook.com/share/1HcmCKUFRD/?mibextid=wwXIfr
Plumbers know one trick window companies almost never mention.
The fog inside a sealed double pane is moisture that bypassed the spacer seal. It does not mean the glass is broken. A defogging contractor (search "window defogging" + your city) drills a tiny hole on the exterior corner, runs a fan or warm air through it for 24 to 72 hours, drops in a desiccant cartridge, and caps the hole with a breather valve. The valve lets future moisture escape instead of clouding the glass again.
This will not restore the original argon or krypton gas fill, so the window loses a small amount of insulating value (roughly R-0.5 of a typical R-3.5 unit). For most homeowners that trade-off is worth it. Full IGU replacement runs $300 to $600 per pane installed; defogging runs $80 to $150 and lasts 7 to 10 years.
Skip the service if the spacer bar inside the glass shows visible cracks or warping, or if the seal failure is older than 5 years with heavy mineral staining on the inside surface. At that point the glass coating is etched and clarity will not fully return. Replacement is the right call.
The Insulating Glass Manufacturers Alliance does not endorse defogging as equivalent to replacement, but most regional glass shops will quote both and let you choose. Get both numbers before you decide. [WV20I]

05/19/2026
05/19/2026