Did you know that a typical duct system can lose up to 20% of conditioned air due to leaks, holes and poorly installed ducts? As a professional, homeowners rely on you to seal and insulate ducts so their home will be safe, comfortable and energy efficient. With the proper know-how you can repair all of your customer's leaky ducts and prevent common heating and cooling complications.


Locating Leaks
Because houses are not static systems and conditions change as houses age, air leaks are common occurrences. Here are some helpful tips to consider when you're locating and sealing ductwork on your next job. Duct joints and connecting points should be inspected in all areas including in attics, crawl spaces and basements of houses. When examining the ductwork for leaks, pay special attention to the seams where any duct opening meets the floor and wall; because these joints are neither sealed nor connected mechanically to the duct system, they are more susceptible to leaks. Every unsealed joint is likely a small leak, even if a hole or gap is not visible.







Sealing Leaks
As difficult as it is to locate leaks, sealing leaks tends to be made simple with the growing variety of duct sealants on the market today. In order to seal ducts correctly, you need to use quality adhesive that will last. Here are some materials that you should use to effectively seal up duct leaks, which will ensure the health and safety of your customer and their house.

Acrylic Duct Sealants
Acrylic duct seal is a versatile latex water-based product that forms a tight and lasting seal. Red Devil RD-DS 181 (639-5913, 5900), is a gray duct sealant used in medium and high-pressure duct systems. It is a special formulation which is non-flammable and provides permanent flexibility, excellent water-resistance and superior sealing strength. This product can be applied to seal supply and return registers, as well as any metal to metal joints in medium to high pressure systems of ductwork.

To apply RD-DS 181 to vents, simply take off the vent cover by removing the screws with a screwdriver. Then, tape off the perimeter around the register. With a caulk gun or a putty knife, apply a generous amount of sealant to the small crevices between the duct opening and the wall.

Tape Duct Sealants
HVAC tapes are specifically engineered to be a high strength, tough and durable solution to duct sealing. Although this type of duct sealant is soft and pliable, it is able to seal both small and large holes in ductwork. With high quality tape duct sealants, like a roll of 2-1/2" x 60 yard foil tape (639-5942), you will not only seal duct vents airtight, but you will also help restore conditioned air to your customer's home.

When using tape duct sealant, make sure the product you use meets both the UL181 and SMACNA AFTS 101-73 standards. These tapes can be especially effective for sealing leaks in straight seams and edges, and for sealing air vents and registers.

To ensure a conformable and effective seal, it is essential that you clean the duct joints beforehand, removing grime and rust from all crevices of the sheet metal. Once the duct work is clean, apply the tape to any leaks in the ductwork. While you place pieces of tape over leaks, make a lasting seal by applying pressure to the edges of each piece of tape with a putty knife.

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