How Air Duct Sealing Works

Air duct sealing is a critical yet often-overlooked component of having an HVAC system working in perfect order. Air duct sealing is maintenance that ensures your ducts are sealed, and your conditioned air is where it’s supposed to be, while the outside air is kept out.

It's important to have professionally sealed ducts, so you can rest easy knowing you won't suffer the consequences of a poorly sealed system. Consequences can include expensive inefficiencies in the system, lower indoor air quality, and even a quicker deterioration of your expensive equipment, appliances, and home.

Why is air duct sealing overlooked when considering healthy HVAC maintenance?

Air ducts are often in the parts of our homes that are hard to access, like basements, attics, crawlspaces, behind walls, and between floors. The downside to the discreet nature of your ducts is that it’s very hard to know for sure whether they are cleaned, sealed correctly, and properly functioning.

Does Air Duct Sealing Help?

Air duct sealing helps your home be safer, healthier, and more energy-efficient

1. Air duct sealing helps with energy efficiency and lower utility bills. 

It’s estimated that in the average home, 20-30% of the air in the HVAC system can be lost due to leaks, with many consequences.

When you lose that much air, you're paying for air that you don't use. That means higher utility bills in the summer and winter, especially when your HVAC system needs to work harder to make your house comfortable. When you get an air duct seal, you may see lower utility bills.

2. Air duct sealing helps your home to safer and healthier.

If the outside air is leaking in through poorly sealed ducts, you may be living with outdoor pollution in your home. Also, leaks can allow byproducts of large appliances to leak into the spaces of your home that should be free and clear. You may have a room that’s extra stuffy or smells like mildew because vapor from your dryer is leaking into it, instead of being pushed safely to the outside of the system.

3. Air duct sealing helps your home be more comfortable.

With less air loss from your HVAC system, it becomes easier to control the indoor environment, and therefore creates the perfect temperature for your family no matter the temperature outside. 

HVAC system and air vents.

Why Is It Important to Perform an Air Duct Test for Leakage?

Now that we know how important air duct leakage is, let's learn how to address the problem. How do you know if you need professional air duct sealing?

You won’t be able to tell visually. Not only is the entirety of your duct system likely inaccessible to you, but the leaks can also be so small that it would be almost impossible to see them with the naked eye.

Leaks can occur from tiny tears in ducts, cracks in old caulking, and even bends or holes made by age, pests, or inefficiencies.

If you've never had an air duct seal or it's been several years, it's important to perform proper tests for air duct leakage. Another risk factor is home remodeling– your system can take on more dust and debris than usual during a remodel, which can overload it and make it more prone to leaks.

How Do You Detect Air Leaks in Your Home?

The Department of Energy recommends that you hire an expert to give your home a thorough and professional energy assessment that you can rely on. An expert will be able to pinpoint problem areas and make recommendations based on their sensitive equipment.

However, if you’d like to do a check yourself before bringing in a professional, you can try the following basic building pressurization test:

  1. Turn off all combustion appliances on a cold, windy day
  2. Shut all windows, doors, and fireplace flues
  3. Turn on all exhaust fans, such as above the stove, in the bathroom, etc.-- basically, any fan that carries air outside
  4. Carry a lit incense stick past places vents that should blow air into your house– if the smoke wavers or is sucked toward the vent, that means there is probably a leak nearby

How Do You Seal a Leaky Air Duct?

There are a few different techniques and materials to seal air ducts, depending on the location and severity of the leak.

One sealant is mastic tape, which is good for straightforward, large sealing jobs. Another common sealant is caulk, great for those hard to tape places. There is also an air duct sealant that can be sprayed inside the duct to seal from the inside, which will be discussed further below.

It is our strong recommendation that you hire a professional if you want to secure your home with air duct sealing. DIY projects can make things worse and be more expensive to correct when professional duct sealers are finally called.

Roll of reflective tape.

Can You Seal Air Ducts From the Inside?

Sealing air ducts from the inside is possible with a sealant called Aeroseal, which was developed in the Lawrence Berkeley National Laboratory to fill building energy leaks.

This sealant was created due to the difficulty of sealing ducts from the outside, especially in extremely hard-to-access duct work. It was and remains a major scientific achievement.

The research team had to find a way to make sealant particulates that were light enough to travel down a duct, and heavy enough to land and fill the leaks in the duct. It was a balancing act that they achieved, and then continued to perfect via optimization of the aerosol and the application process.

What Is Air Duct Sealant Used For?

Air duct sealant is used for filling holes in the costly leaks that can occur throughout a duct system.

The application of an aerosolized sealant is a process best left to an air duct sealing service, as it can be complicated.

Each portion of the duct to be sealed must be sealed from the outside and pressurized to ensure that the aerosol doesn’t leak out. Then, the sealant is sprayed into the duct with specialized equipment.

The goal is for the sealant to find every tiny hole in the duct, and settle around it in order to make a seal.

How Long Does Air Duct Sealant Last?

Many factors determine how long an air duct sealant will last. They can include the age of the HVAC system, the climate in which the building is located, the efficiency of the appliances that rely on the HVAC system, how often the filters are changed, and how well the rest of the system is maintained.

When in doubt as to whether your sealant is holding, perform a test at home, or ask a local professional air duct sealing service. If you notice any signs that your air ducts aren’t working perfectly, a Filterbuy professional will be happy to examine your situation and give you professional, honest advice.

Can You Seal Air Ducts Yourself?

It’s the opinion of Filterbuy and the US Department of Energy that ductwork is best left to professional duct sealers. While you may be handy with a caulk gun, you will have problems accessing the entirety of your duct system and will lack the knowledge that comes from years of experience.

Choosing to work with a professional has many long-lasting benefits, while DIY air duct sealing can leave you and your home open to many problems.

Woman talking on the phone.

How Much Does Air Duct Sealing Cost and Is It Worth It?

The cost of your air duct sealing will depend on the size and age of your system, the state of maintenance, the climate in your area, and the amount of time since your last duct cleaning and seal.

If you’re the kind of homeowner who wants their HVAC system and large appliances to be working as perfectly as possible, wants to save money by being more energy-efficient, and wants to maintain the health of the home through the elimination of indoor air pollution, air duct sealing is worth it.

Benefits of Air Duct Sealing Services

The benefits of air duct sealing are many, and the downsides are few.

Benefits include:

  • Lower energy bills due to increased efficiency
  • Higher indoor air quality
  • Increased longevity on HVAC-connected appliances

The only downside will be wishing that you had done it sooner when there was less leakage!

It’s better late than never to take care of air duct sealing and your home. Indoor air quality is one of the important factors to your overall health and the comfort of your home. Air duct sealing is a big part of maintaining indoor air quality.

Ready for Air Duct Sealing?

Filterbuy professionals are dedicated to helping you maintain the highest possible indoor air quality through targeted services such as air duct cleaning and dryer vent cleaning. We focus on healthy air in your home, to give you the gift of peace of mind.

Filterbuy offers thorough, expert, detailed air duct cleaning, to help you know that your ducts are in working order. Professionals have the tools, knowledge, and capabilities to get into the nitty-gritty of your air ducts, and they will be sure to leave your air ducts sparkling clean, which is crucial for your indoor air quality and comfort in your home. In addition, Filterbuy also offers a service that you need more often than you think: dryer vent cleaning.

Put simply, Filterbuy is dedicated to providing the peace of mind that comes through allowing experts to take care of your home as if it were their own. We’re committed to educating our customers and letting them know when they can handle a problem themselves, and when they should turn to a professional.

While you may find DIY air duct seal articles out there, it is our strong belief that it’s better to place such an important task in the hands of a professional. No matter how handy a person is, they simply don’t have access to the tools, knowledge, and experience that a professional brings to the table. Our Filterbuy air duct cleaning experts are hyper-focused on what they do best, to allow you to relax and do what you do best while enjoying a healthy, happy home.