Inline fans are basically what moves air through the ventilation ducts as seen in grow rooms. For the high efficiency and quietness of the ventilation system, the fan is preferably mounted on the inside part of the room, where it had direct access to the inside space whose air is to be ventilated. As a result, the quietest inline fan for grow room is mostly preferred above all others.

Quiet Inline fan is a must-have for a grow room, which apart from the basic task of air circulation for the plants’ benefits, they offer completely silent operation without disturbance. This would make the grow room very convenient during the time you would spend there.

Although having the quietest inline fans for your grow room doesn’t contribute any major direct benefit to the plant. However, it makes the area very conducive for you to take care of them.

Amongst our inline fans for grow room, TerraBloom is the most recommended for an effective, and quiet operation. It boasts a 1050CFM air flow rate, along with wireless speed control and overheats protection for a safe, effective and quiet operation.

Also Read: How to purify air from smoke

3 Essential Features to consider in choosing the quietest inline fan for grow room

  • Noise level:

in this article, the most paramount quality we are considering is how quiet the fan is. Having a quiet inline fan could be the difference between a grow room with a conducive atmosphere and not. Since you are going to be spending a lot of time in the grow room, you should as well make it as convenient as it can be.

  • Good airflow with a Variable speed controller:

A quiet fan that is unable to do its basic task of air circulation would be totally useless. This is why although the fan should be quiet, it should also be able to circulate air effectively between the room and external environs.

Air flows are measured in CFM, and the higher, the better. Also, the fans should have a variable speed controller for increasing or decreasing its speed accordingly.

  • Overheat protection:

Overheat protection is a very useful feature for protecting the fan from getting damaged early. This protection system shuts the fan off as soon as it heats above a certain temperature, preventing damages to the motor and equally its bearings.

Top 4 quietest inline fans for grow room

1) TerraBloom ECMF-250-R, Quiet 10″ Inline Duct Fan with wireless speed controller

TerraBloom ECMF-250-R, Quiet 10" Inline Duct Fan with wireless speed controller
  • Powerful aerodynamic design impellers

Its motor is awesome. The sheer power of this motor allows it to run very fast, with an air circulation rate of 1050CFM. This figure is very impressive, therefore enables it to serve large sized rooms with relative ease.

Its mixed-flow impellers are also aerodynamically designed in a compact and tight metal casing. This design also features the fans’ blade, which spans 10 inches in size for helping the product move more air time than that of a smaller blade.

  • Quiet operation

Although an inline fan cannot be completely quiet due to its capacity, if there is any product that fits the silent bill amongst inline fans, it would be the TerraBloom ECMF-250-R. The fan is built with a dual bearing system, which allows the motor to run very smoothly, as well as quiet enough.

  • Overheat protection

At temperatures beyond 140 degrees Fahrenheit, the fan would cease to work, as it would trigger the safety switch. This should be avoided as much as possible due to the large tendency of the excess heat that could deform the product. For this reason, the fan should not be mounted in a high-temperature area.

  • Wireless speed control

The fans speed can be varied across different levels, depending on what you want. There are six different speeds to choose from, and switching between these speeds is done with the help of a wireless speed controller. The remote sensor works as far away as 50ft, making it a very useful addition to the fan, which is sure to keep you away from getting into your attic or crawlspace, just to vary its speed.

This fan only works with TerraBloom wireless speed controllers and no other type; therefore, if there is damage, the exact same type has to be ordered from the manufacturer. This product also doesn’t come cheap, being the most expensive on our list.


  • it operates very quietly,
  • long 10-inch fan blades for wide range coverage,
  • comes with a wireless remote speed controller,
  • aerodynamically designed impellers affords it an airflow of 1050 CFM,
  • it is powerful enough to serve large sized areas,
  • an installation kit is included with the purchase,
  • overheat safety switch,


  • the device only works with TerraBloom speed controllers,
  • it is the most expensive product on this review list,

2) AC Infinity CLOUDLINE S8, Quiet 8″ Inline Duct Fan with Speed Controller

AC Infinity CLOUDLINE S8, Quiet 8" Inline Duct Fan with Speed Controller
  • Capacity and Precise speed controllers

The capacity in airflow rates is amongst the most impressive qualities possessed by this fan. The S8 series at 807 CFM, is able to circulate air in large-sized grow rooms very effectively. This feature is coupled with precise speed controllers, which gives users the flexibility of controlling how fast the air moves.

There are eight different available speeds to choose from, with the first allowing the fan to roll at low RPMs without causing it to overheat.

  • Quiet operation and energy-efficient

As icing on the cake of this digitally enhanced fan, it operates very quietly to match its high capacity. This is achieved by it being built with a system that utilizes an electrically commutated motor, which allows it to be controlled using pulse width modulation.

All these come together to give a much quiet operation than ordinary motors. The use of this motor also makes it very energy efficient too.

  • Smart programmable sensors

Asides its 807 CFM air flow rate, it possesses other numerous intelligent features to help enhance overall performance. The first of which is a smart programmable controller, which has a sensor rod mounted on the inlet side, for measuring temperature and humidity of the atmosphere. This programmable controller allows users to control atmospheric conditions in the grow room with precision.

Other intelligent features are seen in the presence of an inbuilt speed controller. This allows the user to vary how fast the fan would run, depending on your ventilation target. Also, there is a timer which is used for limiting the fans running hours, along with an alarm system.

  • Synchronous cloudline connection

This is a feature peculiar to AC infinity cloudline products. It allows the connection of several fans of the same or different models together (must be cloudline products), forming a system that is more powerful in overall performance than each individual fan. The devices can be connected for a higher airflow rate, or to balance static pressure or to share the same programming.

  • Mixed flow design

This design simply protects the motor from external bodies like liquid and dust, yielding a longer life as a result. It also provides the fan with a high static pressure rating, allowing to deliver good airflow levels in situations where air movement is restricted. The fan can also be mounted in any direction due to its dual bearing that keeps the motor running in any way.


  • Mixed airflow design combined with an electrically commutated powered motor for very quiet and energy-efficient performance,
  • smart programmable precise temperature and humidity sensors with timer and alarm system,
  • mixed airflow design helps it maintain peak performance in high static pressure environments and protects against dust and liquids,
  • synchronous cloudline connection for more effective performance,
  • precise speed controller,
  • high airflow rate of 807 CFM


  • mounting could be difficult,
  • due to screws being located inside the mounting block.

3) Panasonic FV-20NLF1 WhisperLine Remote Mount In-Line Spot Ventilation Fan 

  • Airflow rate

The Panasonic FV-20NLF1 is designed for multiple task ventilation. It means that, with this fan, one ventilate the air from two different rooms, through two different ducts, which would be both connected to the fan. This is possible through a double suction blower wheel that moves air quietly. It is designed to draw in air from two sides, allowing more area for air to find its way to the wheels. In numbers, it possesses a good airflow rate of 240CFM, making it suitable for small to fairly large grow rooms.

  • Quiet operation

Designed for light use in residential areas, this fan is very quiet while operating. Although it is able to exhaust fan from multiple points, it still manages a noise rating of 1.3sones, which is really quiet, and wouldn’t be a nuisance in your grow room. They are quiet enough to not even be noticeable times while running.

  • Durable and energy-efficient

Firstly, its motor system is designed specially to operate at much lower temperatures. Normally, the higher the temperature of the motor gets, the more likely it is to get damaged or wear out, especially its bearings.

This design gives a durable and long-lasting motor. Also, for even further durability, the bearings are permanently lubricated, ensuring that wear doesn’t take a toll too early.

Asides the good motor design, the fans casing is made of gauge zinc galvanized steel, which is also painted to protect it from rust. With such material, be rest assured that you would conveniently get years of service before cracks start to appear.

Lastly, being an energy star rating, this product consumes a considerably lesser amount of energy while operating, hence just a little increase in energy bills.


  • good airflow rate of 240CFM makes it suitable for medium and fairly large-sized rooms,
  • operates very quietly at 1.3 stones,
  • good durability gives it a long life, energy star certified and consumes little amount of energy,
  • leading to less overheating and motor failure.
  • Code compliant: ASHRAE 62.2, LEED, California Title 24 and Washington VIAQ


  • it does not support variable speed switches,
  • and is also controller selective while the purchase comes with none.


  • Includes a three-year manufacturer warranty.

4) Hon&Guan Inline Duct Fan Exhaust Fan 311 CFM, Powerful & Quiet Mixed Flow Inline Fan 

  • Easy duct connection

The inlet and exhaust point of this fan is infused with plastic clips. These clips hold the duct firm as soon as it is connected to the points. The ducting edges are made of metals, unlike the rest of the plastic body, which helps make the connection firm.

The combination of metal connections and clips helps create an overall firm connection, but also makes it easy to detach the duct when the time for maintenance.

  • Quiet and energy-efficient

Made of completely plastic body and blades, noise is very far away from this fan. The plastic is durable to an extent, although not like that of a metal casing.

It operates very quietly, a feature that is also down to the application of a mixed flow design, coupled with a pulse width modulation controlled motor. This system also makes it very energy efficient, consuming far less energy compared to conventional fans.

  • Speed controller with overheat protection

With a speed controller, the motor can be controlled to run on either the high or the low, without making any humming sound. It offers users the flexibility of tailoring the fan’s performance to specific needs. Overheat problem is also another common problem with fans, but prevented in this device.

As soon as the motor gets heated beyond 140 degrees Fahrenheit, it simply shuts off to prevent damages or early wearing of its bearing.

  • Mixed flow design and Waterproof

Another cool thing about this device is that it is waterproof. Waterproof in the sense that it can function in an atmosphere of high humidity content, without getting damaged.

However, it should never be exposed to water directly, or dipped in one, as that would damage the fan. For further protection, a mixed flow design also helps in moving air in areas with high humidity content.


  • plugs at inlet and exhaust points for easy duct connection,
  • operates quietly and is very energy efficient,
  • contains thermal overheat protection for preventing damages,
  • variable speed controller,
  • moisture and dustproof design,


  • relatively low airflow rate of 311 CFM,
  • vibrates excessively due to its plastic build.

How to make a loud inline fan quieter – 4 Effective Simple ways 

There are several ways through which a loud inline fan can be made to be quieter, and they are:

  • Place the fan in a sound-absorbing box:

This is simply covering the fan with sound-absorbing surfaces like a cardboard or wood casing. This helps absorb a large percentage of noise generated by the fan, greatly helping with its overall noise generation.

  • Install a speed controller:

Speed controllers help limit the speed in which the fan runs. Fans running at maximum capacity generate the highest amount of noise, therefore reducing its speed would also reduce the noise generated to an extent.

In doing this, however, you risk not achieving the desired airflow rate or even damaging the fan completely. This is why we recommend you only install a compatible speed controller or install additional fans to up the airflow rate when reducing the fan’s speed.

  • Attach a fan silencer:

We recommend you make use of a neoprene clamp for joining the fan and silencer. They are able to make it fit properly, as well as preventing vibrations that could cause more noise. Attaching a silencer to the fan also greatly reduces the noise.

  • Insulate the duct or use a duct muffler:

Insulating the whole duct system or adding a duct vent muffler would go a long way in reducing the noise produced. Make use of insulations like fiberglass or using an inline fan duct muffler could reduce the noise produced to as low as 25dB.

How to soundproof a Grow room – Best Method 

The best way to have a soundproof grow room for those with a good budget is to simply purchase a soundproof grow tent. They come in several shapes and sizes and are completely silent, even when standing next to them.

Many also offer additional features like lights and fans. On the other hand, soundproofing a grow room could be quiet tasking, depending on what size and nature it is.

Sound can be kept inwards by making use of egg cartons for padding the walls, while weather strops could be used to seal up floor gaps. Ensure you seal up every other opening that could allow sound through.

Final Verdict on the picking the quietest Inline Fan for grow room

TerraBloom ECMF-250-R is clear of any other fan for your grow room, both in quietness and performance. It is very quiet, blending in easily with the background in a grow room, and not lacking a bit in performance. With 1050CFM and 10-inch blades, it is able to draw air over a wide area and grow room size. For damage protection, its design prevents overheating from occurring too.

The AC Infinity CLOUDLINE S8 is just right behind in our recommendation. Being a fully digital device, it possesses programmable temperature and humidity sensors, as well as a precise speed controller for conditioning the atmosphere to users’ taste.

It also boasts an 807 CFM airflow rate, and mixed airflow design for moving air even in atmospheres with high static pressure while keeping the air and liquid contaminations away. We would not forget to mention the special synchronous connecting option available to all AC Infinity CLOUDLINE products, allowing users to create a more efficient and effective system.

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