You’ve had your annual heating system tune-up and sealed the air leaks in your home, and now you’re ready to save money when colder weather arrives in Georgia, right? Well, maybe not. If you haven’t sealed your ductwork, you may be paying more than you should for your energy bills. The typical home’s duct system loses between 25 and 30 percent of the air that moves through them. Leaky ducts are a major source of energy waste, and sealing them properly is essential for lowering your energy bills and your carbon footprint.
The Anatomy of Ductwork
The ductwork in your home originates at the supply plenum of the furnace, which is the metal box on top of the unit that collects the warm air to be distributed through the ducts. The trunk duct is the first section of ductwork, and it eventually branches off into several supply ducts that lead to the supply registers around the house. Ducts are typically installed in sections. Whether your ducts are made of flexible material or rigid sheet metal, these connections can become loose over time due to vibration and leak out a considerable amount of air.
Detecting Duct Leaks
The best way to evaluate the air tightness of your ducts is to have a professional energy audit performed. An energy audit will also identify other areas for improvement to increase the energy efficiency of your whole home.
You can conduct your own energy audit as well, although it won’t be as accurate as the professional version. Turn your thermostat to FAN ON and light a stick of incense. Slowly pass the incense along the ductwork and watch the smoke. When it wavers, flows away from the ducts, or is sucked into the ducts, you have a leak.
Sealing Leaky Ducts
Never use cloth duct tape to seal your ductwork. Duct tape dries out quickly and deteriorates rapidly. Instead, use UL-listed metal tape or mastic duct sealant. Carefully wrap the leaky joints with the tape, pressing down firmly to seal, or apply the sealant with gloved hands or a cheap paintbrush. Mastic should be applied to the thickness of a nickel.
In addition to sealing loose joints, check the seal between the trunk duct and the supply plenum and between the ducts and the supply registers. If you detect large gaps in these locations, use self-adhesive fiberglass mesh to close the gap, and cover it with a nickel-thick layer of mastic sealant.
Insulate While You’re At It
If you have ductwork that moves through spaces that aren’t conditioned, such as the garage, attic, or basement, insulating them can save you even more money on your heating and cooling bills. Insulation keeps the air inside the ducts at the optimum temperature as it passes through. It also helps prevent condensation, which can result in the growth of mold in these spaces.
For more expert tips on detecting and sealing leaks in your ductwork, or to schedule an energy audit with one of our skilled technicians, please feel free to contact us at Comfort Control, Inc.