I counsel my clients and friends (okay, anyone who’ll listen) to seriously consider rebuilding old wood windows before replacing them. The old growth wood is irreplaceable. Not to mention, most replacements can not match the appropriate look. And, in many cases, rebuilt windows can match the thermal performance of replacements. Don’t buy into the vinyl window salesman’s pitch. Vinyl may last forever but those windows will need to be replaced in just a few years. I don’t have any personal experience with this company but I have heard good things.

http://cmgreenewindows.com/