According to the U.S. Department of Energy, in a typical house, 20% of the air moving through the ductwork system is lost because of duct leaks.
Duct leakage forces your HVAC system to work harder and longer in order to meet the temperature setting on your thermostat. Leaky ducts also cause "bad" air from your basement, crawl space or attic to be drawn into your system and distributed throughout the house.
Duct sealing is an affordable energy-saving upgrade that will pay off by improving interior comfort and air quality while reducing your utility bills.
Along with duct sealing, it's worthwhile to have at least some of your ductwork insulated. If you have ductwork located in crawl space, basement and attic areas just think how cold or hot these areas become at different times of the year. Insulating ductwork in these areas will prevent cooled air from being heated by hot ducts in the summer. In wintertime, insulated ductwork protects heated air from frigid temperatures in a crawl space or attic.
These are affordable energy-saving upgrades that require no maintenance or replacement ever. You pay for these upgrades once and then enjoy improved comfort and energy savings for as long as you own your house.