How Do Duct Fan Silencers Work?

By Kent Gruetzmacher
Published: September 19, 2022
Presented by AC Infinity Inc.
Key Takeaways

Wondering whether to add a duct fan silencer to your growroom gear? If you’re looking to keep things quiet, then a duct fan silencer is the perfect tool for the job.

The success of any indoor garden is largely tied to the equipment that makes things happen behind the scenes. From environmental controllers to exhaust fan systems, different technologies work in symphony to create the perfect equilibrium for growing cannabis plants indoors. While equipment like grow lights is essential to overall plant health, hardware such as duct fan silencers serve a different function — it ensures your growroom isn’t a nuisance for people.


While indoor gardens offer great privacy and protection when compared to outdoor operations, indoor grows can still draw unwanted attention. Inline fans can produce enough noise to disturb housemates or expose your garden to neighbors. Whether you using inline fans for air-cooled lights or exhaust systems, silencers diminish the noise output of fan motors and rushing air.

From rock and roll music to growroom equipment, all sounds are created by soundwaves. In borrowing from recording studio design, duct fan silencers are engineered specifically to absorb the sound waves that are produced by inline fans. By absorbing sound waves, duct fan silencers create a quieter home environment and increased garden security.


What are Duct Fan Silencers?

Duct Fan Silencer inside a grow tentDuct Fan Silencer | Credit: AC Infinity
Duct fan silencers are tools used to reduce noise from inline fans and airflow within ventilation systems. While they are widely used for indoor garden exhaust setups, duct fan silencers are also used to reduce the noise of inline fans in bathrooms, kitchens, and laundry rooms.

Regardless of their placement, the goal of any duct fan silencer is to muffle the noise created by soundwaves, while also allowing air to move through exhaust systems unobstructed. Ultimately, duct fan silencers muffle intrusive sounds, while also ensuring hot, humid, and stale air can be moved unobstructed from laundry rooms, bathrooms, and growrooms.

Premium duct fan silencers like those made by AC Infinity utilize high-grade foam shaped in a wave crest pattern to diminish noise pollution by up to 50 percent. These duct fan silencers have aluminum flanges on both ends that seamlessly attach to both ducting and inline fans with standard clamps. As such, with the right silencer, you can arrange your inline fan and ducting to meet the noise control demands of nearly any growroom or tent.


How Do Silencers Make My Inline Fan Quieter?

In the most basic sense, silencers make inline fans quieter by absorbing sound waves. In turn, weakened sound waves cause sound to dissipate. When air moves into the silencer from your inline fan, its baffles give sound waves room to expand. Next, when the sound waves interact with the air pockets contained in the foam walls, the sound waves get trapped by the empty space in the foam.

Finally, with the energy of the sound wave trapped in such small spaces, molecules from the sound wave collide with one another and dissipate the energy of the wave. In the end, this intimate molecular exchange is what provides noise reduction in duct fan silencers.


When companies like AC Infinity design their duct fan silencers, they add as many baffles as possible to reduce noise, without also restricting the cubic feet per minute (CFM) rating of inline fans. This design process represents a very careful balancing act between form and function.

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What Size Duct Fan Silencers are Available?

cannabis plant in a grow tent Equipment manufacturers make duct fan silencers for all sizes of inline fans and ducting — ranging anywhere from 4 to 16 inches. That being said, if you are running an exhaust with a 12-inch inline fan, you will want to match your system with a 12-inch silencer.

It’s also worth noting that cultivators use duct fan silencers for a variety of applications in the growroom. To illustrate, if your air-cooled light system is powered by a 6-inch inline fan, you should match the fan with an appropriate silencer. This same process obviously applies to intake fans.

Where Should I Mount My Duct Fan Silencer?

No matter what its intended use, you should position your duct fan silencer on the outtake end of an inline fan. To this end, you can mount the silencer directly to the fan or add a piece of ducting between the two pieces of equipment. Please note, since the job of a silencer is to absorb sound waves, the closer you mount it to the inline fan, the fewer chances sound waves have to escape from excess ducting.

If you have ample space in your growroom, it’s fairly easy to mount the silencer directly to the inline fan when setting up an exhaust system. By situating your carbon filter, inline fan, and silencer directly in a straight line, you can keep noise at bay, while also ensuring that your inline fan puts out the desired CFM.

If you are growing in a tent, it will likely be impossible to have all three pieces of equipment in a perfectly straight line. In such instances, adding a curved piece of ducting between the fan and carbon filter will allow you to curve your whole setup and fit it into the tight confines of a tent. However, you will likely sacrifice a little bit of CFM from the whole exhaust.

Whether you don’t want your garden to draw the attention of neighbors, or you simply don’t want to hear the hum of a fan in your living room, silencers can be a great addition to any indoor garden. While most cultivation technology is designed specifically to create environments where cannabis plants thrive, occasionally engineers make equipment with people in mind as well. All things considered, duct fan silencers are not a necessary piece of equipment, but they are quite helpful in ensuring your indoor garden doesn’t disrupt your daily life.

By borrowing methods from music recording studios, duct fan silencers are designed specifically to capture and dissipate sound waves. To function at their best, silencers must have enough baffles to trap sound waves, while also not slowing the CFM of inline fans. No matter if you need a duct fan silencer for exhaust systems, air-cooled lights, or intakes, they will help create a more quiet, secure, and relaxing environment by diminishing noise output.

AC Infinity logo

AC Infinity is the foremost name in air delivery systems, designing and developing the latest innovations in cooling and ventilation technology. They offer a suite of quiet inline fans that automate the growing progress and track key metrics. Visit or contact [email protected] to learn more.


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Presented By

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Written by Kent Gruetzmacher | Writer, Owner of KCG Content

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Kent Gruetzmacher MFA is a Colorado-based writer and owner of the writing and marketing firm KCG Content. Kent has been working in the cannabis and hydroponics space for over a decade. Beginning in California in 2009, he has held positions in cultivation, operations, marketing, and business development. Looking specifically to writing, Kent has worked with many of the leading publications and marketing agencies in the cannabis space. His writing has been recognized by such icons as Steve D’Angelo and Rick Simpson.

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