I want to keep using our perfectly good anodized aluminum frame thermopane windows from the 1980s. They are clean and do most of the job very well. They are just not low e argon modern windows. So what! They are very durable and very narrow framed. I can't say that about the Vinyl replacements I have been offered. I want a glass shop to fabricate a single pane window in a frame that fits just inside of our existing window and can be sealed to prevent moisture from getting between it and the old window. That should give enough insulation to prevent moisture from condensing or freezing on the inside glass like our old ones. I think they are not interested in doing a cheap job so they won't consider this. Anyone got an opinion?