Is your home feeling drafty? Are your energy bills higher than they should be? You might be losing a significant amount of conditioned air through leaky ducts. In fact, it's estimated that the average home loses about 30% of its airflow due to duct leakage. Let's dive into what this means, why it's important, and how you can fix it.
Your duct system is the circulatory system of your home's HVAC (Heating, Ventilation, and Air Conditioning) system. It's a network of tubes that distributes heated or cooled air throughout your living spaces. When your ducts leak, it's like having a hole in a garden hose – water (or in this case, air) escapes before it reaches its intended destination.
As homes age, duct systems often begin to show signs of wear. One of the most common problems is air leakage, especially at weak points in the system. Duct leaks are typically found in a few predictable areas:
Duct sections are joined together using seams and mechanical fasteners. Over time, these connections can loosen or separate, allowing conditioned air to escape into unconditioned areas like attics or crawl spaces.
Where your ductwork connects to the supply registers and return grilles, leaks often form due to poor sealing or shifting over time. These areas are frequently overlooked during installation and can be a major source of energy loss.
The plenum is the central hub of your duct system—the area where air is collected and distributed. If this part of the system isn't properly sealed, it can lead to significant air leakage and reduced HVAC performance.
Flexible ducts, often found in attics or crawlspaces, are particularly vulnerable. Improper installation, sagging, or tearing can all lead to leaks that reduce airflow and comfort in your home.
Duct leaks don’t happen all at once. In most cases, they develop slowly as your home and duct system age. Here’s how:
Older duct systems were often sealed with cloth duct tape, which isn’t meant to last forever. As the adhesive dries out, the tape peels away, leaving gaps where air can escape.
Pests like rodents or insects can damage ducts by chewing through insulation or flex duct material. In some cases, ducts are crushed or punctured during maintenance work or by stored items in attics and crawl spaces.
As your home settles over time, the movement can cause ducts to pull apart at the joints. Even small shifts can create gaps that reduce system efficiency.
Extreme heat and cold—especially in unconditioned spaces—can cause metal ducts to expand and contract. These repeated movements can weaken seals and loosen connections, leading to slow, hidden leaks.
The methods and materials used for sealing ductwork have evolved over the years.
Prior to 2000, duct tape was commonly used to seal ducts. However, duct tape is not a long-term solution as it degrades over time. Other methods included mastic sealant, but application was often inconsistent.
Today, more effective methods and materials are used:
As mentioned earlier, it's estimated that the average home loses about 30% of its conditioned air due to duct leakage. However, the actual amount can vary significantly depending on the age and condition of the duct system. This means that almost ⅓ of the heated or cooled air leaving your HVAC system never makes it to those uncomfortably hot/cold rooms!
The goal for duct tightness is to minimize leakage as much as possible. A well-sealed duct system can reduce air leakage to less than 5%.
There are a few telltale signs that your duct system might be leaking more air than it should. If you’ve noticed uneven temperatures or excessive dust, your ducts could be part of the problem. But while these signs can point you in the right direction, the only way to truly know what’s going on is to have a professional energy audit.
While every home is different, these issues often suggest duct leakage:
These signs are helpful, but they don’t tell the whole story. A home energy audit gives you measurable data by using tools like a blower door and duct leakage testing equipment. This allows us to find out exactly how much air your system is losing—and where it's going. In many cases, even homes with new or well-maintained systems are leaking far more than the ideal threshold of 5%.
At Atlas, we don’t guess. We test, measure, and help you prioritize the right solutions for your home.
While basic sealing methods like applying tape or mastic may provide temporary improvements, the most effective way to seal your ductwork is by hiring a professional energy solutions company. At Atlas Home Energy, we use diagnostic tools and proven technology to ensure your system is sealed properly and performs the way it should.
One of the most powerful tools available today is Aeroseal®.
Aeroseal is an advanced, patented process that seals leaks in your ductwork from the inside. Unlike traditional methods that only seal areas you can access, Aeroseal targets every leak—even the ones behind walls, in crawl spaces, or deep inside the system—without tearing anything apart.
Here’s what the process looks like when done by our team:
We start by temporarily blocking off the HVAC vents and isolating the system so that no sealant reaches motors, coils, or other sensitive equipment.
We pressurize the duct system using a calibrated fan. With the vents sealed, the only way for air to escape is through the leaks—which is exactly where we want the sealant to go.
A safe, non-toxic aerosol sealant is introduced into the ductwork. These microscopic particles stay suspended in the air until they’re pulled toward gaps and cracks in the system.
As the pressurized air pushes the particles to the leak points, they begin to accumulate and seal the holes—similar to how a tire sealant works. This method can reduce duct leakage by up to 90%, dramatically improving airflow, especially to the rooms furthest from your HVAC system.
Throughout the Aeroseal process, we monitor your duct system’s leakage in real time. You’ll see exactly how much air was leaking before and how much is being saved after. We provide a printed certificate with your before-and-after results, which can be used to qualify for utility rebates and energy upgrade incentives.
When you work with a company that specializes in whole-home energy solutions—not just HVAC installation—you get more than a quick fix. You get a measured, performance-based improvement that reduces energy waste, balances your home’s comfort, and supports long-term system efficiency.
If you suspect your ducts are leaking, or your home has uneven airflow, Aeroseal may be the most effective solution—and we’re here to help you determine if it’s the right fit.
When your duct system is sealed from the inside using Aeroseal®, the difference isn’t just measurable — it’s noticeable. From improved comfort to lower utility bills, Aeroseal delivers whole-home benefits that go far beyond patching a few leaks.
After sealing, many homeowners see airflow at vents increase by as much as two times. That means more air is actually reaching your living spaces — especially the rooms farthest from your HVAC system. The result? Rooms heat or cool faster and feel more comfortable, more often.
When ducts are leaking, your HVAC system has to work overtime to maintain temperature. By sealing those leaks, Aeroseal helps your system run more efficiently and cycle on and off less often, reducing wear and saving energy.
Leaky ducts can cause certain rooms to feel too hot while others stay cold. Aeroseal helps restore balanced airflow, giving your home a more even temperature from room to room — no more playing thermostat games.
Leaks in ductwork pull in dust, insulation fibers, and other pollutants from attics, crawl spaces, and basements. By sealing the gaps, Aeroseal keeps those contaminants out of your air supply — leading to healthier indoor air for your family.
When air flows freely and evenly, your system doesn't have to strain to keep up. Aeroseal reduces stress on motors, fans, and compressors — helping extend the life of your HVAC equipment and reduce the need for repairs.
In Maryland, homeowners can receive a rebate of up to $750 for doing Aeroseal duct sealing, provided they get a home energy audit first. This makes Aeroseal an even more attractive option for improving your home's efficiency and comfort.
Duct leakage is a common problem that can significantly impact your home's comfort, energy efficiency, and indoor air quality. By understanding the causes of leaks and the available solutions, you can take steps to seal your ducts and enjoy a more comfortable and efficient home. Whether you choose DIY methods or professional services like Aeroseal, addressing duct leakage is a worthwhile investment.
Atlas Home Energy
