If your home relies on ductwork to distribute conditioned (heated or cooled) air, duct sealing is one of the most effective and inexpensive projects to improve your home's comfort and efficiency.
In an average home, leaky ducts can waste hundreds of dollars in heating and cooling each year.
In fact, leaky ductwork often accounts for 10 to 30 percent of total energy costs. If the duct leakage is 20% of the total airflow, the efficiency of a cooling system can drop by 50%. Heating efficiency is similarly affected. Duct leakage also lowers heating and cooling capacity, and can shorten equipment life. Many comfort complaints in homes are due to the efficiency-robbing effects of leaky ductwork.
While the increase in energy costs is significant, protecting health and safety is of equal importance. Ducts are usually located in the attic, crawl space or basement. If the return ducts leak, they draw air from these areas directly into the home. This air can be contaminated with dust, mold, excess humidity, and potential toxins like radon, and pesticides sprayed to control termites and carpenter ants. If the leaks are bad enough, they create lower pressure inside the living space, further drawing in contaminants.
If you use gas to heat water, cook your food, dry your clothes, or heat your house, you should know that these appliances release gases such as carbon monoxide in small quantities through their ventilation systems. Leaky ductwork in your heating and cooling system may cause “backdrafting,” where these gases are drawn back into the living space, rather than expelled to the outdoors. So there’s a safety issue to consider, as well as one of energy efficiency. Sealing ductwork minimizes air quality issues, and we also recommend that all houses have a carbon monoxide detector along with the smoke detectors that are standard, and often required, home safety equipment.
Ductwork is often neglected simply because it's largely hidden away behind walls or between floors, out of sight and out of mind. Older homes are more likely to have serious leaks, due to both age and to the fact that less attention was given to efficiency and the important role of ductwork in years past.