The Best 6 inch Inline Fan 2019 - Review of the Quietest Exhaust Fans For Grow Tents and Rooms

by Sophia Walters  |  August 1, 2019

How to Choose the Right 6 inch Inline Fan For Grow Rooms?

Anyone who’s ever been to a hydroponics shop can tell you that purchasing the right equipment is just as tedious and arbitrary as choosing a shampoo at your local department store. You might have a general idea of what you’re looking for, but you’ll also be bombarded with tons of variations of essentially the same product, most of which do the exact same thing. Whether it’s a 6-inch inline fan, exhaust fan, or vent fan, you’ll most likely end up relying on the recommendations of your hydroponics shop, and you may end up paying way more than what you should have, even for something you really didn’t need in the first place. We know the struggle. But before we can tell you what to buy, you’ll have to know exactly what it is you’re looking for. And to figure it out, you’ll need a basic understanding of how air circulation works.

Did you know? When it comes to growing cannabis inside a building or in a tent, having a good quality inline fan is one of the most important pieces of equipment you need to have. This way you will make sure you have enough CO2 available so your plants can get as much as they need. You also need to make sure that the air doesn’t go stale and is being moved around and replaced with fresh air frequently.

Best 6 Inch Inline Fan Comparison Table


– Designed to quietly ventilate grow tents

– Intelligent controller with thermostat programming


– Ultra-quiet operations

– Energy efficient


– Quiet operation

– Durable ceramic-coated


– Made with quality UL components for quiet operation

– Easily installs in minutes


– Powerful and high efficiency

– Certified for safe use


– 1 year limited warranty

– All steel construction


– Removes 99.5% of volatile from the air

– Suitable for working in 60″x60″, 95″x48″ and above size Grow tent


– Removes 99.5% of volatile from the air

– Run the Ambient Temperature Range:  -20°C ~ 60°C


What is CFM?

Every fan, whether it’s a 6-inch inline exhaust fan or an extractor fan, has a CFM rating, which stands for “Cubic Feet per Minute.” This is basically the amount of cubic feet of air that the fan can move in a minute. Some growers tend to ignore CFM ratings because the primary function of inline fans is to dissipate heat, but that’s only part of what they’re intended to do.

Understanding Plant Biology

On the leaves of your plants, there are tiny pores called stomata, which are essentially the breathing points of your plants. The stomata on the leaves function as a way for the plant to absorb CO2 and oxygen while dispersing water vapor as a waste product in a process called transpiration, at which point the plant will draw more water from the roots. The stomata will behave according to the conditions of the plant and its surroundings. With a bright light and enough moisture available through the roots, the stomata will become dilated, allowing for more CO2 and oxygen to be absorbed. As the soil becomes dry, the stomata will close to preserve water, thereby halting photosynthesis. With too much water (overwatering) the stomata will dilate to release as much water vapor as possible, but at a rate that can be dangerous to the plant’s survival and development.

What does all this have to do with inline fans?

As the stomata releases water vapor as a waste product, this waste must be displaced from the grow room (click here for 4’x4′ setup guide) via inline fans. If you don’t extract enough air, the air will become thick with water vapor, your plants will have less access to essential CO2 and oxygen, and photosynthesis will be disrupted. However, if you extract too much air, you’ll also be extracting all the precious CO2 that your plants need to thrive.

Maximize Your Yield – Infographic –

Simply put, you need to use your inline fans correctly to find the sweet spot for your air circulation.

Calculating CFM

Did you know? The general rule of thumb is that you want to extract all the air in the room every three minutes for ideal circulation.

This allows the plant to absorb all the CO2 it can while also transpiring excess water vapor. If you base your sweet spot around three minutes, the rest of your calculations will involve basic math. Let’s take, for example, a 10’x10’x12’ room. We need to find the cubic feet of the 3’x3′ grow tent, which is expressed by multiplying the length, width, and height: 10 x 10 x 12 = 1200 cubic feet That’s the amount of air we need to displace every three minutes. But since fans are calculated per minute, we need to divide our cubic feet by three to find out how much cubic feet of air we need to displace per minute, which will be our ideal CFM: 1200/3 = 400 CFM So, for a 10’x10’x12’ room, we know that we need a single 400 CFM fan to extract all the air within three minutes. Although this doesn’t take into account various turns in your ducting that slightly restrict airflow or intake fans that you may have pushing fresh air into your grow space, this is generally going to be in the ballpark of what you’re looking for in your fans. Now that you have a better understanding of CFM ratings, check out this comparison of various 6-inch inline fans on the market:

Reviewing The Best 6 Inch Inline Fans

Product Name







  •  351 CFM
  •  6.5 Pounds


  • Intelligent controller with separate temperature and humidity programming works with a fan speed controller, timer and alarm system.
  • The inline ducted construction has a mixed flow design which is powered by a PWM-controlled DC motor for quiet operation.
  • Designed to be used with grow tents and hydroponic control rooms. It can transfer heating and cooling, cool AV closets, and help remove odors.
  • The kit includes a corded sensor probe, AC power plug, duct clamps and mounting hardware.
  • Energy efficient. Up to 40% cheaper to operate.


  • During operations, the sound of the air rushing through the duct is very audible.
  • It may sometimes stop working due to problems with temperature and humidity controller.

The AC Infinity CLOUDLINE T6 is a ventilation exhaust fan built specially for grow tents. It has an automated temperature and humidity controller, as well as a cooling booster. It can be coupled with a carbon filter to remove odors in the grow box. 


  • 347 CFM
  • 66 Watts
  • Double Insulated Wall for Noise and Humidity Reduction
  • Quick-Removal Clipping System


  • Great for small to mid-sized grow rooms​
  • Comes with ducting​​
  • Runs very quietly
  • Great style and design
  • Insulated walls
  • 10 year warranty


  • It can only move air at 347 CFM
  • No filter

At first glance, the Vortex S-600 seems like a beast of a machine. A superior build quality and fancy design will certainly turn some heads in your grow room, and may even justify its price tag. But don’t be fooled. You won’t get much more out of the S-600 than most other fans on the market, and despite Vortex’s claims that this is an “ultra quiet” fan, the S-600 is pretty loud. If you’re looking for a quiet inline fan with a decent price tag, look elsewhere.


  • 400 CFM
  • Metal Housing
  • Durable Ceramic Coating
  • Mounting brackets include


  • Operates very quietly
  • Ceramic coating for durability
  • Thermally protected AC motor
  • Top-notch molded impeller
  • Comes with all the necessary mounting parts and hardware
  • UL-recognized components


  • No speed controller
  • No ducting
  • A little heavy

“Could even outperform some 8-inch inline fans” Say what you want about Active Air inflating their CFM numbers, but if you’re looking for a fan that does what it intends to do, Active Air’s 6” Inline Fan certainly does the job. It’s relatively quiet, and could even outperform some 8-inch inline fans on the market when it’s used correctly. The mounting brackets certainly help as well; mounting fans is always a pain, but the brackets make things a whole lot easier.


  • 435 CFM
  • Steel Housing
  • Powder coated finish
  • Mounting Brackets Included


  • Very efficient
  • Noiseless operation
  • Professional quality
  • Durable powder coated finish
  • UL rated components
  • Comes with an 8ft cord


  • Doesn’t include a speed controller
  • Doesn’t include ducting
  • It can withstand up to 104°F

Hurricane fans are usually good investments, and their 6-inch 435 CFM model is no exception. The steel housing and coated finish certainly add to the quietness of the fan, and $90 for 435 CFM is certainly tempting when you’re looking for a competent fan for your grow space. The only problem with the fan is how the mounting brackets sit on the housing; you might have a hard time drilling the brackets in with how they’re seated against the housing. But that’s a minor concern for a top quality inline fan.


  • 353 CFM
  • Extended collar for ducting
  • Moisture resistant
  • Vibration-free


  • Vibration-free operation
  • Easy to install
  • Permanently lubricated ball bearings
  • Can withstand up to 140°F
  • Ideal for hydroponic growing
  • Cost efficient


  • It only includes one bracket
  • No filters
  • A little loud

Yescom is a relatively unknown brand in the hydroponics air flow market, but names don’t mean much when you’re looking for fans anyway, especially when you consider that the Yescom claims 353 CFM for $65.95, which is far cheaper than a lot of other brands. Although we can’t promise the fan will be all that quiet, the design itself is pretty solid. The extended collar is similar to the Active Air, and should meet your air circulation needs just as well if you’re not worried about brand names.


  • 240 CFM
  • 37 watts
  • All steel construction
  • Powder coating


  • Offers all of the basics required
  • Lightweight with aluminum construction
  • Works well and quiet
  • Easy to use
  • Lots of CFM
  • Inexpensive


  • Not very durable
  • No accessories included
  • No warranty

It’s pretty loud. The VenTech may seem far inferior to the other fans we have listed here based on 240 CFM, but we couldn’t complain with a price tag of about 20 bucks. Granted, it won’t do much for an entire grow room, but if you’re running a stealth box grow with only a few plants, the VenTech VT DF-6 may be for you. It’s pretty loud, but you can’t expect much with such a low price tag. To be honest we do not recommend this fan.


  • 442 CFM
  • Metal fan blades
  • 95 watts
  • Carbon Filter and Ducting Included


  • Comes with a carbon filter and duct fan
  • Made of high-quality steel
  • Good for hydroponics
  • Plenty of options
  • Can operate up to 185°F
  • Highly effective


  • No speed controller
  • No warranty

It’s not always a good idea to buy fan and filter combos because you can generally find cheaper alternatives if you buy them separately, but the iPower package is a real deal. Considering you’re probably going to need charcoal filters and ducting anyway if you’re trying to run a 442 CFM fan, the iPower package could be saving you money. iPower is generally pretty consistent with most of their products, so you can bet the filter and ducting are going to be quality products. Big plus – Cotton Pre-Filter cover is included for your filter so you can increase the filter’s longevity.


  • Comes with just about everything you need
  • A speed controller is included
  • The fan runs pretty quiet
  • Carbon filter features a good size
  • Can remove almost all smell from the room
  • Reasonable price


  • The fan tends to slow down a bit after a few months of use
  • It may get noisy after some time
  • Ducting could be stronger

This amazing 6-inch inline duct fan combo from Growsun is specially designed for grow tents to make the most out of indoor yields. At an attractive price, you also get an activated Virgen carbon filter, 25 feet of ducting, 30-yard duct tape, speed controller, durable clamps, and a pair of metal hoop. That makes it a tempting offer for cannabis growers wanting to save their time and money.

Running at 400 CFM, the fan keeps the air odor free and makes the planting environment fresh all the time. This low-noise device comes with mounting brackets for easy installation. Thanks to the speed controller, you can easily adjust the speed of the fan according to your own needs. It’s possible to switch between three settings: Full Speed, Variable Speed, and OFF. According to the manufacturer, this fan can remove 99.5 percent of the volatile substances from the air.

In addition to the 6-inch inline fans, there is also a matching 6″ carbon filter that is 1.5 inches thick for the best results. By cooperating with the inline fans it ensures the stability and safety of your grow room.

As mentioned above, you also get a duct tape that is 30 yards long as well as 2 inches wide. Not only that it sticks well to any metal surface but also involves an environmental water glue for enhanced safety.

Please note that this product fits 56″ x 56″ x 80″, 60″ x 60″ x 80″, and 95″ x 48″ x 80″ grow tents, but you can also use it larger sizes as well. It will get the job done for sure.

ipower set in work

Shopping for fans can be tough, but if you just do the math, you’ll know exactly what you need.

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