Quietest Inline Fans – [2021 Reviews]

Inline fans are great for shifting large volumes of air. But they can be noisy! Even the quietest inline fan will still make some noise. 

In this article, we'll be reviewing 10 of the quietest inline fans you can buy. 

What if you've already bought one and you don't want to spend more money buying another? How can you make your inline fan quieter? We offer some great tips for that below these reviews.

Top 10 Best Quiet Inline Fans Reviews

OUR TOP PICK

AC Infinity Cloudline S6 Quiet Inline Fan

AC Infinity CLOUDLINE S6, Quiet 6” Inline Duct Fan with Speed Controller - Ventilation Exhaust Fan for Heating Cooling Booster, Grow Tents, Hydroponics

Designed to transfer cooling/heating to any room, circulate air, exhaust odours and cool AV racks, the AC Infinity CLOUDLINE S6 may be the best quiet inline fan for your grow room. 

If you’re looking to grow plants indoors this inline fan is designed specifically to ventilate grow tents. And it does it quietly with a low noise output of only 32dBA. 

It doesn’t take long to set up. The kit also includes a corded AC power adapter, installation manual, as well as all the mounting hardware you’ll need. You also get an 8-speed manual speed controller that uses PWM (pulse width modulation).

It shifts 402 CFM which is plenty for the price. The extra airflow does make it a bit louder than the T4 fan which does about half that.

What makes this fan so quiet? The mixed flow design is combined with an EC-powered motor which allows the fan to operate really quietly.

These EC motors are also around 40% more power efficient so you’ll be spending less on your utilities bill.

EDITORS CHOICE

TerraBloom 4' Silent Inline Booster Fan, 47 CFM, Intake Quiet Mixed Flow Energy Efficient Blower for Air Circulation in Ducting, Vents, Grow Tents

The fan is built and designed to exhaust and intake air through 4” ducts as quietly as possible. What’s great about this fan is that the sound pressure level at full speed is only 25 dBA. It’s quieter than a whisper which is measured at 30 dBA!

What you do end up hearing at its lowest speed is a bit of an electrical hum but it’s not a deal breaker. We would just rather run it at full speed all the time so you don’t hear the hum. 

For the low noise you end up sacrificing air flow though so these are really meant for low flow applications. It’s perfect for a small grow tent though.

The fan shifts 47 CFM and consumes just 9W of power. You could opt for the 6” model if you need to shift more air. That model is rated at 188 CFM.

Just be aware that the fan isn’t suitable for carbon filters or static pressure applications. It’s a great option for a low noise simple air exchanger in an RV or small grow tent. 

BEST VALUE

iPower 6 Inch 442 CFM Inline Duct Ventilation Fan HVAC Exhaust Blower for Grow Tent, Grounded Power Cord

If you want a quiet inline fan at a budget price then the iPower Inline Duct Fan could be a good option. Budget price doesn’t mean it’s a bad fan though. It is just a basic powerful unit without a speed controller. 

Also, at 65dB it’s not the quietest inline fan. But it shifts plenty of air (442 CFM) and would be a good budget option if your grow room is in the basement. 

It’s really well put together so there’s no rattling to add to noise or lead to breakdowns.

Another advantage to getting this fan is that it has a permanently lubricated bearing that doesn’t need any maintenance. 

The fan is also made with a durable ceramic-coating so it’s not going to rust and will look good for longer too. 

We really liked how versatile this fan is. You could use it in an industrial application just as easily as you could for household and horticulture ventilation.

RUNNER UP

Tjernlund M-6 Inline Duct Booster Fan, Hydroponic Blower Heat Air Conditioning Vent Exhaust, 460 CFM, 6'

While this fan is a bit pricier than the other two, we recently spoke about, it’s definitely worth considering. It’s a great option if you need to shift a lot of air or need to vent a large room. 

It would also work well if you want to move heated or cooled air from the ground floor up to the first floor of your house. It’s far cheaper than installing additional air conditioning.

The blades are designed to run for long periods of time without slowing down. Even though the power output reaches 460 CFM, it operates quietly. 

We also like that the noise levels don’t seem to change too much as the speed increases. If you want to control the speed you can adjust it on the fan itself. 

If you prefer to control your appliances with a remote there are remote control devices available for the fan. 

A huge bonus is that you also don’t have to worry too much about the setup of this fan which can sometimes be a concern for us. It comes with all the brackets that you need and the hardware it comes with is easy to understand.

Installation is simple and, if done properly, you get zero vibrations.

RUNNER UP

AC Infinity CLOUDLINE T4, Quiet 4” Inline Duct Fan with Temperature Humidity Controller - Ventilation Exhaust Fan for Heating Cooling Booster, Grow Tents, Hydroponics

This is one of the more expensive fans we reviewed but it’s also one of the more durable. For most of us, we don’t mind buying something expensive if we can have the peace of mind from knowing we won’t have to spend money on it anytime soon. 

With an impressively low 28dBA noise output this is one of the quietest inline fans on the market. 

Much like the AC Infinity CLOUDLINE S6, the fan has been designed with a PWM (pulse width modulation) -controlled DC or EC-motor that means it can run quietly. It also means that this fan is energy efficient, which is great. 

So what’s the difference between the AC Infinity CLOUDLINE S6 and the T4? 

The T4 shifts half the air that the S6 does and uses around 30% less power. Because of this it’s around 4dB quieter than the S6.

We really like the temperature / humidity control of this model. The S6 just has a programmable speed control.

The prices of the T4 and S6 are only a few dollars apart. Your decision is really going to be made on how much air you need to shift, how quiet it has to be and if temperature / humidity control is a must.

RUNNER UP

VIVOSUN 6 Inch 440 CFM Inline Duct Fan Vent Blower Ventilation Fan for Grow Tent ETL Certified

This fan is perfect for getting rid of bad smelling odours in bathrooms and workshops or you want to ventilate big spaces. 

The Vivosun helps to boost airflow in HVAC units, removing the odours and exhausts you don’t want. And of course, it can be used to bring fresh air into grow rooms.

It shifts plenty of air and does it quietly. You get an airflow of 440 CFM at a really low noise level of 50dB. This makes it one of the quietest inline fans at this power level.

Everything about the construction of this fan feels tight and solid. There are no rattles or squeeks so it stays whisper quiet even at top speed.

After a while of use you may want to grease the fiber washers to keep it nice and quiet. The fan is easy to take apart to get to these.

This fan really stands out amongst others for its durability. The blades are also made for long service life and quiet operation.

But that’s not all. The drive system includes a permanently lubricated bearing which allows for smooth and quiet operation. 

RUNNER UP

Can RS8HO High Output Centrifugal Inline Fan, 737 Cubic Feet Per Minute

If you’re looking for serious power but want to keep it quiet then this is a good option. It’s pricey but the performance and durability make it worth considering.

It shifts 737 CFM and produces a surprisingly low 10.5 sones, or around 62dB.

We really like that it has a 5 year warranty.

We also like that the mounting bracket it comes with doesn’t move a lot, so it doesn’t make a big noise when the fan is on. 

Besides that, the fan delivers smooth spinning at high speeds. It’s safe to say that this fan really won’t be a bother.

RUNNER UP

TopoLite 4' Inline Fan Carbon Air Filter Ducting Combo for Grow Tent Exhanst Kit and Hydroponic Indoor Plants Growing System

This is a nice combo kit if you’re looking for a quiet inline fan with some carbon filtering.

The prefilter is attached using velcro which makes it easy to change. We like that the filter uses coal based activated carbon which is environmentally friendly. You can put this straight in the recycling once it’s done its job.

It’s easy to set up and comes with all the bits and pieces you need to install it.

The thing we really like about the TopoLite 4” is that its really quiet. At 50 dB the low noise fan will vent your grow room without you even hearing it. 

It also has the composite fan blades and center hub that help to reduce noise and vibrations. 

RUNNER UP

Hydroplanet™ 4 Inch Duct Fan,Exhaust Booster Fan High CFM, 4' 65-100 CFM (4 Inch)

The Hydroplanet fan is one of the cheaper ones, but it does the job. If you’re looking for a cheap online fan that’s still fairly quiet then it’s worth considering if you’re on a budget.

It’ll move 65 CFM at around 56dB fan noise. There aren’t any bells and whistles so it’s ideal for very basic applications.

Even though the blades are made from plastic, it has a 2 year-warranty which is better than some of the more expensive fans.

RUNNER UP

TerraBloom 10' Inline Duct Fan, Quiet Energy Saving EC Motor with 0-100% Adjustable Remote Speed Controller. 1065 CFM, 150W.

These fans are designed specifically for indoor grow rooms and vertical farms. These are probably some of the most efficient and quietest inline fans on the market.

You get plenty of airflow at a maximum of 946 CFM with the fan noise ranging from 45 to 65dBA at maximum speed.

If you’re concerned about power usage then the efficiency of these fans are a nice bonus. It hits top speed using just 126W of power.

It comes with an easy to use speed controller and we really like that you don’t get any humming noise at low speeds like some of the cheaper inline fans do.

The included speed control dial lets you adjust between 0 and 100% speed. There’s an optional wireless control available too that allows speed changes in 6 16% increments.

What Are the Sources of Noise in An Inline Fan?

Perhaps you’ve already bought a fan, but it’s way too loud. Instead of spending money on a new fan, it might be better to look at what you can do to reduce the noise your fan makes.

But before we get into that, we need to understand what the cause of the noise is. 

Fan Speed

Fan speed is one of the most obvious reasons for why your inline fan makes a noise. You’ve probably noticed that your car makes more noise the faster you drive.

It works exactly the same way for an inline fan. When the fans run at high speed, they blow a lot of air and this is what makes the noise. The principle is the same for when you choose the quietest range hood.

If you are looking for a quiet inline fan, buy a fan that provides you with the CFM you need. If you buy a fan that gives you more CFM than you need, you could end up buying a fan that’s too noisy. 

The more CFM, the more potential there is for noise. So first, calculate the CFM you’ll need for the room you’re going to place your inline fan in. 

Vortex Shedding

Vortex shedding (specifically vortex shedding in air) has to do with the air separation that the trailing edge and the blade surface of the fan makes. This noise is a result of air separation caused by the trailing edge and blade surface. If your fan has serrated or notched blades, a good blade profile and a proper pitch, you won’t hear as much of the noise. 

Turbulence

Turbulence is another reason for why your fan might make noise. Turbulence in a fan happens when the airflow stream is interrupted by bends, sharp edges or inlet and outlet disturbances. 

Structure Vibration

Vibrations are caused by any mechanisms or components that have come loose in the fan. Motor mounting, bearings, rotor to stator eccentricity, and residual unbalance are some of the things that might come loose and cause that unwanted noise. These are the same issues that make even the quietest ceiling fans make a noise. 

Now that we know where the source of the noise comes from, we can look at how to reduce the noise. 

How to Make an Inline Fan Quieter

Here are some things you can do to quieten your noisy inline fan:  

Isolate Your Inline Fan with Cardboard or a Wooden Box

 This being one of the simpler strategies, it may be the best one to follow. By enclosing your fan with a noise-absorbing surface, you can lower the noise of your inline fan. You can use household materials that you might have around the house, like wood or cardboard. But any rigid or hard surface that absorbs sound will do. 

If you don’t mind spending some extra cash, you can also purchase a ready-made inline fan silencer box. While you can make your own DIY fan silencer box, it might be easier for you to buy the box ready-made. 

Hang Your Fan Above the Ground or Another Surface

If you like to place your inline fan on the floor or a table, you’ve probably noticed the vibration it creates. And, with vibration, comes noise. So, the solution to this problem is to suspend your inline fan from the ceilings and walls. How? If you place your inline fan in the DIY fan silencer mentioned earlier, you can suspend the box with the inline fan inside. You can use Bungee Cords to help you do that. 

Insulate Your Inline Fan’s Ducts

If your inline fan has a metal duct, it can be a huge cause for the noise your fan makes. So, what can you do? You can insulate your inline fan’s duct by using fibreglass as insulation. ThermoFlo is a good product to use if you decide to insulate the duct. 

Get A Duct/Vent Muffler

An inline fan duct muffler’ is an advanced version of insulating your inline fan’s duct. It’s way more efficient. A duct muffler can reduce the noise your inline fan makes by 25 dB (decibels). You have the option to make your own duct muffler, or you can buy a ready-made duct muffler. 

Soundproof the Room

The next solution is more about blocking out the noise than actually silencing your inline fan. By using the right materials, you can successfully soundproof your room. It’s not difficult to do and you won’t have to worry about completely restructuring your place.

You can also use vinyl or soundproof curtains to block out the sound. But, if you want the room to be more vibration and soundproof, use stronger materials like rubber. 

Use A Speed Controller

The faster the fan, the nosier it can get. That’s where the speed controller comes in. The speed controller will allow you to control the speed of your fan which will ultimately give you control over how much noise your fan makes. 

There is something you should be aware of though, which might be obvious. You can end up buying a speed controller that’s not compatible with your fan. If this happens, it’s most likely that the fan will break sooner than expected. 

What to Consider When You Are Installing Your Inline Fan

Building codes

Before you install your inline fan, you need to know what the building codes are for inline fans. You can talk to a building inspector about the requirements for the installation of the fan.

You’ll want to discuss the duct size, length of runs and electrical installation. You need to remember that you might have to get planning permission before you can install your inline fan. 

Where You Place Your Inline Fan

The best place to put your inline fan is near the main exhaust port.

Condensation 

Condensation can damage your inline fan quite badly. You can prevent this by installing a condensate drain line. How does it work? It will drain excessive moisture away from the fan motor. 

We’ve reviewed some of the quietest inline fans on the market. While some of them may seem similar it's worth comparing noise levels, speed control and optional extras before purchasing one.  

Also, when it comes to quiet inline fans don't get too hung up on 1 or 2 dB of noise level. You're not going to be able to hear the difference but you may end up paying a lot more.