I have been visiting Clearvue since I was a kid. My dad owns a small glass company and always buys his glass from Clearvue. We buy many types of glass here, but they're known for their excellent thermal panes. Now and then, the rubber seals on thermal panes get punctured and the gas inside escapes. Moisture gets in between the panes of glass, which looks like fog, and they lose their insulating value. This is when you know it's time to replace your thermal panes.
Thermal panes really are not that hard to replace. I have replaced many of my own fogged units because my houses have old windows. Thermal panes typically last something like 15 - 20 years before they need to be replaced.
Clearvue only sells glass to glazers. People who install glass for a living are called "glazers". So you can't just walk into Clearvue and by glass. You're better off calling a glazer. However, they do offer top notch products. read more