Hi - I have a 40 year old passive solar house with wood wondows. Some of the windows are fogged between the panes. I don't know if I need replacement complete windows, or if I should try to just replace the glass in the problem windows. I have had some trim work done over the years. All the commercials I see talk about UV ray protection. We have just plain glass, I think. I have read quite a few articles on your website regarding this issue. I have about 35 windows, half of them @45" x 72". I had a replacement estimate that made me ill, and that was just for vinyl, which you guys don't like. I live in Colorado, and am just totally confused and discouraged. When I call to set up appts., a few of the companies have no opinion on windows for a passive solar house. Any advice would really help. Would it be worthwhile to try smaller windowcompanies? I have stuck with the major US brands.