Had four windows "defogged" by specialists in Florida. They hooked us up with water and power like an RV Park, removed the windows and replaced them. Clear as new. Two years later we discovered one of them had not have the sealant strip along the top frame of the largest window. Leaking for two years turned the wall into a nightmare requiriing some major replacementof the inside walls, and more. The Company had offered a nice warranty, but by the time we went to Florida it would have been expensive - not worth the trip. We had the window sealed locally. In summation, windows can be cleared up, and there are quite a few Dealers around, just be aware of problems that may come in the future.