I have a material that has a ½” thick polypropylene core a non-conductive material with a high-grade aluminum foil backing. This material will stop the conductive heat to cold transfer. Remember heat seeks cold. Never wrap a duct with a double-sided foil material because the foil is super conductive. The premiere microfoil is a green building material, which is totally safe and environmentally friendly material. Mold will not grow; it is a no itch material. And has a really good r-value. You can use this material to stop pipes from sweating also. This material is a perfect thermal break. Call Dan Biermann at 602 528-3645 for more info or e-mail me at sales@microfoil.com

Good Luck and Best Regards Dan Biermann