How's your sealing? Not the one overhead -- the sealing of your home's ductwork. The answer to that question can have an impact on both your health, and your wallet. Tightly sealed ductwork keeps contaminants from entering the system and circulating throughout your home. But despite its name, duct tape is the wrong material to use. Instead, ducts should be sealed by a professional using mastic -- a high quality compound that assures maximum energy efficiency.