Beginner growers often underestimate how much it takes to create the perfect growing ecosystem inside a room or a grow tent. While the lights, nutrients, and spacing are all important, the ventilation also plays a key role.
Your plants need light for photosynthesis, and an inline fan takes care of heat control, humidity control, pest control, and overall air quality.
Our top picks reflect just how similar inline fans may look to an outsider but how different they really are when it comes to operational performance when we look into the best inline fan - complete reviews and comparisons survey.
Best Inline Fan Reviews
1. Vivosun Inline Duct Ventilation Fan
When you find a reputable brand, it’s important that it makes the right-sized fan for your needs. Luckily, Vivosun offers inline fans of 4, 6, and 8-inch diameters.
The midrange Vivosun inline fan is a very solid choice for many home growers. It reaches a maximum fan speed of 2450 RPM while offering airflow of 440 CFM. But such a powerful fan doesn’t come without its drawbacks.
50dB noise levels may seem acceptable at first but the vibrations are a lot more annoying than the noise of the fan itself. This fan does come with its own leather muffler which is impressive. However, it is not the most efficient one on the market. You may need to make some DIY adjustments to further lower the noise.
One thing that’s great is the variable speed controller. This is something every inline fan should have, but sadly that is not the case. It will help you adjust the noise level from the fan and from the vibrating ducts. Also, it helps you find the proper speed for pushing out the heat.
The pricing is very good for all Vivosun inline fans. In your grow tent setup, you will have to put it next to your own carbon filter. Vivosun doesn’t offer a fan and filter combo.
What's to like about the Vivosun Inline Duct Ventilation Fan
The build quality is very impressive. The fan has multiple galvanized steel components treated to resist atmospheric corrosion, even though this is not necessary given the low humidity of grow tents.
What's not to like about the Vivosun Inline Duct Ventilation Fan
The fan doesn’t come with any ducting or high-quality mounting brackets.
2. iPower Inline Fan
iPower makes grow tents and every type of growing and monitoring equipment you may need to start growing your own plants. The company’s inline fan is one of the best on the market.
This inline fan is rated at 442 CFM. This is a desirable value for small and medium grow tents. For larger grow tent, the inline fan may still work, but it just won’t be as efficient at creating a proper airflow.
The noise level is under 50dB even at full load. The noise is kept under control by the center hub which reduces the vibrations created by the composite fan blades. The fan also has ceramic coating which acts as a very good protective layer against humidity.
iPower also makes a wide range of growing equipment for use with this inline fan. There is special ducting, a carbon filter, and even a fan filter. Using those items in your setup would make the ventilation unit even tighter and less noisy since everything is made to fit.
This 6” diameter fan has enough RPM and CFM to maintain a steady temperature and keep the humidity under control. Although it has a solid build, this iPower inline fan won’t operate well in an ambient temperature of over 80 degrees.
But, to you the grower, this shouldn’t be a deal-breaker. Most cannabis strains need a steady temperature way lower than 70 degrees anyway.
What's to like about the iPower Inline Fan
What’s very nice about this iPower midrange inline fan is that it doesn’t require any lubrication on your part.
What's not to like about the iPower Inline Fan
Although there are many accessories available for this fan, none of them are included in the base package. If you want a filter, ducting, or even a speed controller, you have to pay extra.
3. Vortex S-Line S-600 Inline Fan
This 6” diameter fan is one of the cheaper units in Vortex’s S-Line. The line is recognized for its energy efficiency and low noise.
The unit is just 10” tall and shaped like a barrel. The motor and the blades are housed inside double insulated walls, which helps a lot with noise reduction. The casing is made from high-impact polycarbonate which makes it quite durable.
As part of the quiet operation design, there’s also a built-in backdraft damper. This not only helps reduce the noise even further but also increases the fan’s efficiency when it comes to getting the temperature, humidity, and dust particles under control.
Unlike many other inline fans you’ll see, this one also features a very easy-to-use mounting bracket. This saves plenty of time and some money as the S-600 is basically ready to go out of the box.
The S-600 is rated at just 347 CFM. However, due to its decent RPM rating and medium fan diameter, it’s still good enough to handle most medium-sized grow tents on its own. Another thing that helps is the unique motor design which uses mixed-flow dual impellers.
What's to like about the Vortex S-Line S-600 Inline Fan
The ease of use and ease of installation are the two areas where this inline fan excels. The fact that it has a solid mounting bracket and a compact barrel design also helps.
What's not to like about the Vortex S-Line S-600 Inline Fan
The unit is not very cheap to begin with. This is why it’s also a bit disappointing to see that a speed controller is not added in the base package. You’ll have to pay extra to get its controller.
4. Hurricane Inline Fan
This is designed as a commercial-grade inline fan which means that it has both high-end performance and a top-of-the-line casing built to outlast the competition.
You have a choice of the Hurricane inline fan in 4, 6, 8, 10, and 12 inches in diameter. The 6” model is best suited for medium-sized tents but works just fine in small tents since it operates at variable speeds.
As far as value goes, you would be hard-pressed to find a similar combination of durability, power, design, and ease of use at this price. The casing is all steel and comes with a cool powder-coated finish.
What’s very nice, and what most fan manufacturers often overlook, is the extra-long power cord. This inline fan features an 8ft cord which shouldn’t need any extension to reach an outlet.
The airflow rating is 435 CFM which is more than enough for small, medium-sized, and certain larger grow tents.
What's to like about the Hurricane Inline Fan
As great as the all-steel design is for durability, the compact size is what makes this fan even more special. It allows growers to optimize their space allocation so that there’s enough ducting between the ventilation ports, the fan, and the filter.
What's not to like about the Hurricane Inline Fan
It is surprising that at this price point the fan doesn’t come with a speed controller. Instead, the manufacturer just recommends using an aftermarket Titan ventilation controller for optimum compatibility and performance.
5. TerraBloom Inline Fan
This model has a metal centrifugal exhaust for its main feature. However, TerraBloom makes a wide range of inline fans of various diameters and matching carbon filters.
This is a 6” inline fan that boasts a 410 CFM rating. It has a compact size and more than enough power to handle grow tents of all sizes and configurations.
Its design allows it to be paired with carbon filters as large as 6 x 36 inches. Because of this, it is very good at controlling heat, humidity, and overall air quality in most grow tents.
The speed controller is included. However, there are some minor downsides to this TerraBloom inline fan – a rather short grounded power cord, a mounting bracket that only works on flat surfaces, and a duct connection that’s hard to adjust for anything else other than 6” ventilation ducts.
What's to like about the TerraBloom Inline Fan
What’s more impressive is that despite the power of this TerraBloom inline fan, there’s not a lot of noise to worry about.
What's not to like about the TerraBloom Inline Fan
Although having a speed controller is great, being able to only slow down the blades to 50% of the maximum output may not be enough for certain tasks.
The Importance of Using an Inline Fan for Growing Cannabis
A grow tent or a grow room can ensure an endless growing season. However, in order to reap the benefits, there are many factors you need to monitor and control. All plants have their own unique requirements when it comes to temperature, light, nutrients, etc.
Inline fans are one of the most essential pieces of control equipment for indoor growing enclosures. They help you control four very important aspects of growing plants in a controlled climate:
Plants absorb a lot of CO2. This is why they’re so good at cleaning the air for us. But if you want your plants to flourish, you can’t let them drown in this stuff. Of course, you can’t deprive them of it either.
This is how the ventilation system helps. It brings in a constant supply of CO2 from outside the room or tent while also pushing out hot air. This helps keep the levels constant.
Prevent plant diseases and pests
Mold, mildew, fungus, spider mites – these are all hazards. Pests are attracted to damp places and especially damp topsoil. If you’re not using a hydroponic system in your grow tent or room, chances are your plants will attract them.
A ventilation unit helps keep the topsoil dry enough to be unattractive to pests. It also creates an air current that can push some of them out. Of course, for inline fans to be effective like this, you will need a fine mesh setup around the ventilation holes – both for the intake and exhaust.
All plants need some level of humidity. But too much or too little and things can quickly go awry. Ventilation systems can push out some of the water vapors accumulated in a closed space.
It also disposes of most of the excess heat which also contributes to humid conditions.
Push out excess heat
Most grow lights give out plenty of heat. Some emit more heat than others. Although not enough to cause us problems, it’s enough to mess with the plants. Even the slightest temperature change can make or break your crops, especially if you want to grow cannabis.
A proper ventilation system gets rid of all that excess heat and keeps the temperature at a steady value throughout the day regardless of the outside temperature.
Now that the importance of inline fans has been established, find out what specific features you should look for when buying yours.
Almost everything about an inline fan has something to do with the growth tent. Starting with the diameter – which is usually 4, 6, or 8 inches – you pick an inline fan that fits the opening in your grow tent’s fabric.
Of course, you can also do it in reverse. First, pick the type of fan you want and then find a tent frame that supports its weight and has the right-sized openings. Also, keep in mind that fans really do come in all shapes, sizes, and weights.
Don’t assume that all 8” fans are heavy. The air movement though increases with the diameter.
CFM stands for cubic feet per minute (cu ft/min). This is the rate of airflow (expressed in volume) in or out of a space. You find this measurement on many cooling systems such as computer cooling systems but also on inline fans designed for grow tents.
This value should match your grow tent capacity. The bigger your growth tent is, the higher the CFM rating should be (in order to move the appropriate volume of air per minute).
Variable speed is key. An adjustable fan will allow you to maintain a certain temperature with a higher degree of accuracy. And, depending on where you install your grow tent or what materials you use for covering it, you may need the speed controller to be adjustable over a wide range.
The speed will often also impact the noise levels dramatically. If the fan is too fast, keeping it on all day long might be almost unbearable. But the design of the fan and the quality of the motor also have a say when it comes to noise.
Fan materials vary a lot. Here you have two factors to consider with respect to the casing. First, you need to consider the weight. If your tent frame can’t support the fan, then it’s no good.
Secondly, you want to consider the durability. It doesn’t matter if the fan is light if it is likely to burn up after a few weeks due to unreliable components. You might also want to check the UL ratings as this certification determines the durability of the contraption.
Also, it doesn’t hurt to check if the fans have self-lubrication. This ensures a solid performance out of the box and less maintenance on your part.
Even if you’re only planning on maintaining a 4×4 or 4×5 grow tent, the inline fan is going to be subjected to constant stress. No matter how well-built it is, it can still be damaged by power surges. In any event, you should make sure you’re covered by warranty.
The minimum warranty on offer is 12 months. Don’t settle for anything less.
Inline Fan FAQ
What is an inline fan?
An inline fan is a fancy way of describing a fan that is mounted through a wall, ceiling, or ducting. Depending on the type, design, and materials used, some inline fans work better than others in humid conditions.
What does an inline duct fan do?
When used in a grow tent, it’s generally combined with a carbon filter to suck out excess CO2 from the tent. It is also used as a temperature regulator because it sucks out air from the top of the tent, where the air is always hotter.
At the same time, an inline fan brings in fresh oxygen and CO2 so that the plants have plenty of both to feed on. It basically creates a proper and steady air flow that caters to whatever the plant’s demands are.
How to install inline duct fan in grow tent?
The setup is pretty much standard for all grow tents. When you install the fan, make sure that the intake vent is placed towards the carbon filter. That way, the fan sucks out all the excess CO2 from the tent and pushes it out through the duct.
The duct has to be connected to the back of the inline fan and to the ventilation port in the tent’s fabric. It’s a good idea to add some more duct tape around the ventilation port to create a tighter seal.
Although an inline fan can serve multiple setups, this is not advised for marijuana grow tents. Even when dealing with multiple grow tents, you may want to use individual fans and carbon filters to optimize the crop’s oxygenation.
How inline fan works?
An inline fan, also known as an inline duct fan or inline exhaust fan, is a fan used for extraction purposes. However, unlike most traditional fans, this design is made to be housed inside the ceiling.
As the air gets sucked into the intake vent, it gets pushed through a duct. Because inline fans are made to work with ducting and because they are very powerful, you don’t lose as much efficiency as you would if using other fans.
Inline fans are also used in grow tents. Only, those are a bit different than regular inline fans used in the house. The motor doesn’t need to be as powerful or heavy, because the fan is usually hanged on the frame of the tent.
How to quiet down inline fan?
There are two main reasons why an inline fan makes noise. It could be either the fan itself is vibrating too much due to poor craftsmanship or poor choice of materials, or it could be the rambling caused by vibrations in the duct.
There are a couple of ways to reduce the noise made by an inline fan. One of them is to always use an insulated duct instead of a regular duct. Another is to use a duct of slightly larger diameter in order to reduce the vibrations caused by the air being pushed out.
A fan speed controller may also be a good alternative. However, this is only worth using if reducing the fan speed doesn’t mess up the temperature in the tent. Another cool trick is to leave your duct suspended instead of attaching it to the frame.
If all else fails, just buy a muffler. Most of them are cheap enough, though you could also make your own if you’re good with your hands and have the proper equipment. Keep in mind that DIY mufflers may not have the same impact as a store-bought one.
Inline fans are noisy, and not all of them are easy to set up. That being said, having the best inline fan in your grow tent is the only way to maximize your yield. You won’t grow anything if you can’t maintain a steady air flow and the proper air quality and temperature.
That’s what inline fans are all about. There are many manufacturers that make straight fans and combo fans, and some might push you to get other equipment to go with their inline fans. Keep in mind that most of the time, inline fans will work with just about any carbon filter.
You only have to worry about the CFM rating and their durability, not necessarily the bells and whistles. As you can see from our top picks, stressing too much about the little details doesn’t make the search end faster.