Why Is Duct Sealing Important?

Most traditional homes use central air, meaning ductwork is embedded throughout the property. While it’s an efficient way to meet homeowners’ heating and cooling needs, it can also leave room for many issues.

One problem is leaky ductwork. If it’s not handled appropriately, it can lead to unfiltered air travel around someone’s home. Furthermore, those leaks can become a breeding ground for mold, which will increase the likelihood of respiratory issues for the occupants.

As a contractor, it’s your job to ensure that you seal any leaky areas during ductwork inspections to prevent further damage. We’ll provide insight on the different types of duct sealing methods, plus additional benefits homeowners will get from sealing their ducts.


How Do Duct Leaks Happen?

When a client calls you for an HVAC service and thinks they might have an issue with their ducts, they’ve likely experienced some “symptoms” such as:

  • Spikes in their energy bills
  • Hot or cold spots in rooms
  • Increased dust or airborne particles
  • Stuffiness throughout their home


If any of these problems have been referenced, there could be a possible duct leak caused by:

  • An aging system
  • Broken seals between duct connections
  • Loose sections from a low-quality installation
  • Rodents living in and maneuvering through your ductwork


What Should You Do During a Ductwork Inspection?

Although homeowners might try to inspect ducts themselves, they won’t know how to find and fix the problem. That’s where you come in. With your professional expertise, you’ll be able to guide them on the best course of action.

Here’s what you should do during a ductwork inspection:

  • Inspect the entire ductwork system—attics and crawl spaces included
  • Assess the system’s supply and return air balance. An imbalance leads to inconsistent heating and cooling
  • Repair or reattach ducts
  • Seal registers and grilles
  • Add insulation in unconditioned areas
  • Improve ductwork performance by adding new filters. Then test airflow afterward


What Are the Different Types of Duct Sealing Methods?

After your inspection, your next step is to seal the ducts. Depending on the issue, there are various ways that you can plug the ducts. Here’s a quick breakdown of the different methods:

1. Duct Sealing Tape

One way to plug leaky ducts is by using HVAC sealing tape, which you can find at any hardware store. This method is less time-consuming than others because all you do is use the tape to seal the faulty areas.

However, longevity will be an issue since it’s more of a quick fix, and most ducts attract dirt quickly. Furthermore, ensure you don’t confuse it with standard duct tape, which you should never use since it’s not regulated to seal ducts.

2. Mastic Duct Sealant

If you don’t mind getting your hands (or clothes) dirty, another option you can use is mastic duct sealant. It’s a gloopy substance with the same consistency as mayonnaise.

Applying the product is simple—all you need is a paintbrush or if you plan on using your hands, ensure you use a pair of rubber gloves. If the gap size is bigger than ¼ inch, you may have to reinforce the area with fiberglass mesh tape, so the sealant is more effective.

3. Aeroseal Duct Sealant

While mastic duct sealant is a great option, it can be challenging to use when you need to seal ducts in hard-to-reach places. It identifies and seals each leak within the ductwork, and there’s no mess involved, so you don’t have to worry about cleaning up too much afterward.

To use this method, here’s what you do:

  1. Block all the registers and vents to pressurize the area
  2. Then with technological help, ductwork leaks are identified and sealed


The process can take roughly an hour but can be longer if there are more leaks. Afterward, you provide homeowners with a certificate of completion. You’ll also supply measurements of the system’s performance before and after the leaks have been sealed.


How Can Homeowners Benefit from Duct Sealing?

Duct sealing is necessary, and homeowners can benefit in a variety of ways, such as:

  • Having better indoor air quality
  • Removing the likelihood of toxic gasses such as carbon monoxide from entering the home
  • Increasing energy efficiency and saving money on utilities


While each home you’ll work on presents different challenges, you can upskill by enrolling in ACCA’s duct diagnostics and repair course. It’s an online course that covers:

  • How ducts work
  • The impact of air leaks from ducts
  • How you as a technician can improve a system’s efficiency


With additional knowledge under your belt, you’ll be able to grow your HVAC business and help various clients.

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