Save Electricity & Money with a Simple DIY Project: Sealing Ducts

Most homeowners probably only think about their heating, ventilation and air conditioning (HVAC) systems when they’re not working. But even if your HVAC system is providing cool air for your house in the middle of the Texas summer, chances are good that it’s not as efficient as it could be.

Around 20 percent of air moving through a duct system is lost because of leaks, holes or poorly connected ducts, according to the U.S. Environmental Protection Agency. Losing air means that your system has to work overtime to keep your house at the desired temperature, which increases your electricity bills.

While a leaking duct isn’t good (there are several safety issues that accompany it), it does present an opportunity for you to save energy and money.

How To Spot Inefficient Ductwork

First, you need to identify whether you have any leaks or poor connections. According to the ENERGY STAR website, these are some ways to identify if your ducts are losing air.

  • Some rooms are difficult to heat or cool
  • Some rooms constantly seem stuffy
  • You have high summer and winter electricity bills compared to houses of similar size
  • Your ducts are located in an attic, crawlspace or the garage
  • Your ducts are tangled or kinked

How To Seal Ducts

Sealing ducts is fairly simple. You’ll first want to look for gaps at places where vents meet floors, walls or ceilings. Once you’ve identified the leaks, clean off the joints to remove dust and other debris.

If you have duct tape on any part of your system, you’ll want to remove it.  Duct tape actually breaks down over time, leaving your seams exposed.

After clearing your joints, you’ll paint mastic, a gummy substance, over the joint. Try to find a water-based mastic if you can because it releases fewer fumes. Make sure there is an even coating of mastic over the joint, and lightly use the paintbrush to get the mastic into each nook and cranny. HGTV Remodels recommends at least a 1/2-inch overlap around any joint, crack, or hole in the duct.

Once you’re done with the mastic, you’ll seal the joint with UL 181-rated tape. UL stands for Underwriters Laboratory, a global, independent safety science company. You’ll want to use tape with a UL 181 rating because it is more flexible, more adhesive and generally lasts longer. Make sure when you purchase UL 181-rated tape that it’s designed for use with mastic.

Once you’ve applied mastic and the UL 181-rated tape, you’re done.

If you’re more of a visual person, HGTV Remodels has a great three-minute video that we’ve included below. It discusses why you need properly sealed ducts as well as the best ways to go about this.

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  1. [...] Further Reading: Energy Star, Sealing Ducts DIY [...]

  2. [...] Sealing and insulating ducts help prevent loss of cool air and improve the air’s movement through the duct system. Homeowners can save up to 10 percent annually on their energy bill when they properly seal and insulate their ducts. [...]

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