Instructions for Using Aluminum Tape on a Furnace Duct
Aluminum tape, or foil tape, is used to seal ductwork, as opposed to duct tape, which is used for everything but sealing ductwork. The importance of properly sealing ductwork cannot be overstated. Research by Owens Corning has shown that unsealed joints in ductwork are the most significant factor in heat loss, with unsealed ducts having leakage rates of up to 24 percent. Fortunately you can seal your exposed ductwork yourself using foil tape. Seal all the seams in your ducts, including the longitudinal seams on round ducts and the corners of rectangular ducts.