I need some thoughts on the subject, please. We had several aluminum double-paned windows installed about 15 years ago, but decided to wait on the others since we had planned to remodel. Remodeling didn't happen, but the heat loss is just too much through the single panes, and they are big. I am not a fan of the vinyl windows due to off-gassing, but now am in a quandary about my two remaining options. (Wood is too expensive and would not "match" our 15-year-old windows, which we won't replace.)

Aluminum: does not qualify for tax credit but is recyclable down the road, which is important to me.

Fiberglass: strong, insulates enough for tax credit, but are they recyclable later? I know glass or silica is used in production, but so are resins. Any off-gassing?

Any thoughts are appreciated!