Does anybody have any experience using "TechFlex Trophy Series" formaldehyde-free flexible ducting? We are looking at replacing our furnace's flex ducting to try to get rid of some nasty heating odors when the heat runs. A contractor gave us a quote and suggested using this new(?) ducting. It claims to be formaldehyde-free and is coated on the inside with some form of silver which is claimed to control fungi, mold, and mildew, and control odors. I googled it but can't find any reviews about its effectiveness. It is more expensive than other flex ducting, but not terribly so. Any info is appreciated.