Has anyone tried a defogging service (e.g. www.defogusa.com) that
claims to permanently repair fogged multipane windows? I'm not sure
exactly how the process works (the web site makes reference to
cleansing and draining the interior window space), but the thing that
intrigues me is that they claim their process restores the insulation
property of the glass. Plus a 20-year warranty against refogging.

Wondered if anyone has tried them.

Thanks,
John