Duct sealing can increase the efficiency of a heating and cooling system dramatically, potentially saving a household $140 annually. Mastic and metal-backed tape are two good ways to seal ducts, since they can withstand higher temperatures than can conventional duct tape.(Source: "A Guide to Cooling and Heating" (pdf), United States Environmental Protection Agency, 2003, p. 16)
RCD #6 Mastic Adhesive sealing material for ducts US$3.00 to US$34.95
