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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)

Duct Sealing Tips:
It has long been known that a well installed and sealed duct system increases equipment efficiency, health, safety and comfort for the homeowner. By properly installing and then sealing ducts, the contractor can diminish the possibility of moisture and mold problems, the potential for back drafting appliances, and the potential of introducing pollutants to the living environment.

Tips on Using Mastic:
- Seal all seams and joints by brushing on
- Use mastic along with mesh tape to bridge the gap and strengthen the seal
- Water based � easy to apply and clean up
- Remains flexible over time as ducts expand & contract