One simple step that you can take toward saving more energy and money in your home is sealing your air ducts. This often involves sealing the joints of your ducts with duct tape. This is not, however, a permanent solution to this problem, despite the usefulness of duct tape.
Because they run through spaces such as attics, basements and crawl spaces, ducts are exposed to high heat and cold, which can eventually lead to joint separation. To permanently seal these gaps, a thick, gooey compound called mastic must be used. To save even more energy, make sure that your ducts are also properly insulated.