Best Grow Tent Fans And Inline Fans
You’ve found the perfect grow tent and chosen your grow lights. Yet, you need good airflow to ensure that air is evenly distributed and often replaced in your grow tent. A grow tent fan setup will help you keep mold away, and even get a bigger yield. Let me help you find the perfect setup for your grow tent…
Best fan on Amazon. Fits great in medium and large tents. Includes a remote control and buit-in timer.
Power and performance to ventilate even large grow tents. Includes a speed settings.
Do I Need Fans In My Grow Tent?
Airflow is essential when it comes to ensuring optimal cannabis growth. Setting up fans lets you calibrate temperature, humidity and replenish CO2. Here are some of the main reasons why you need grow tent fan:
CO2 (Carbon Dioxide)
Like all plants, cannabis needs carbon dioxide to survive. But because grow tents are a closed environment, the CO2 in the atmosphere will quickly be depleted and replaced by oxygen without proper airflow.
Your setup should have 2-way air circulation, so the cool fresh air goes in while the hotter, used air goes out.
Airflow & Oxygenation
When cannabis plants grow in nature, they have breeze to stir them. This helps them to develop a stronger stem and branches, and aids healthy growth.
We all know that plants absorb carbon dioxide and create oxygen via photosynthesis. But they also need oxygen as well, specially during dark hours. Proper airflow ensures that plants always have access to new, clean air.
Pest, Mold And Fungus Control
Even within the controlled atmosphere of your grow tent you can become the target of molds, fungus and pests like gnats and spider mites.
By affording you greater control over the heat and humidity in your tent, a fan can prevent the conditions that allow mold and fungus to grow in your tent. This means that your cannabis plants are also free of the multi-legged pests that thrive on these molds and fungi.
When pests get into your tent, they can be extremely difficult to keep under control. As in most things, an ounce of prevention is worth a pound of cure!
Lowering The Temperature With Air
If you expect to get the best out of your weed plants, it’s important to maintain the temperature in the sweet spot of 70-80 °F.
A grow tent fan gives you one more means of controlling this temperature and counterbalancing the heat generated by your lights.
This is specially important if you use HID grow lights as they put out lots of heat. In some cases, you even need to run your ducting through the grow light fixture to exhaust the hot air most efficiently.
Keep in mind that you need fans even if you have a grow tent heater. Although the airflow lowers temperature, replenishing the air it’s still a must.
Best Fans For Grow Tents
Your setup should not only include a fan to move air around your tent, but also an exhaust inline fan to let the used air out of your tent. First let’s take a look at 5 fan models that can help to further improve air flow and create optimal growing conditions…
Best Oscillating Fan
I found this tower fan from Seville Classic to be the best oscillating fan based on specifications and customer reviews.
This model can oscillate up to 75º being able to cover all of you grow area when placed in a corner.
The Seville UltraSlimline is great for grow rooms because of it’s very small footprint and quiet performance.
It comes with a built-in timer for auto shut-off, which comes perfectly handy for indoor crops and making sure your grow environment is exactly like you want it to be. Plus, it saves on the electricity side.
It’s also easy to use with and comes with a remote control so you don’t even need to enter your grow tent!
- One of the quietest fans, with 58 DB on high-speed setting.
- Fits comfortably in medium and large tents while providing enough air movement.
- Comes with a remote control.
- Built-in timer.
- Some users reported a "clicking" sound when oscillating.
Best Oscillating Small Fan
This device is designed for use as a grow tent fan. With the clip arm designed to attach to any pole between .59” and 1” in diameter. This fan has a good, sturdy fit which will not slide down the pole.
This is an oscillating fan, making sure not one plant is receiving air directly, but the whole crop gets a turn. Check demonstration video on Amazon’s page.
It also has a pretty good range of motion, both horizontally and vertically. The model has a 90 degree horizontal range and a 120 degree vertical range, making it well suited to a wide range of setups.
- Secure and stable when clipped on a pole.
- 2 speed settings.
- Vertically and horizontally adjustable.
- 6” fan blade may be a little small for some setups.
- Some report that the clip arm is “backwards”, but looks fixed in newer editions.
Best Rated Less-Expensive Fan
This small-yet-powerful fan from Honeywell stands at under 11” in height.
Its specially engineered blades allow it to generate impressive air flow. And with 3 speed settings, it’s easy to find the perfect balance for your grow tent.
This device design is very quiet and generates virtually no white noise. Indeed, it is marketed as up to 25% quieter than comparable models. This model should be more than adequate for most grow tents.
This affordable yet powerful fan is a good starting point.
- Variable speed.
- Up to 25% quieter than similar models.
- Power that belies its size.
- While it's really cheap, it lacks quality materials.
Best Oscillating Tower Fan
If you have a bigger taller grow tent this powerful Lasko oscillating tower fan can better distribute air across the top of your cannabis plants.
This fan’s narrow body can fit in tight spots and its circular base that prevents tip overs makes it a great addition to your grow room.
It also comes with a built-in timer, to automatically shut-off whenever you like it (like if you rather your indoor temperature at night was a little higher).
The Lasko Tower Fan includes a remote control and a bright LED display so you can control it from the outside of your grow environment.
- Remote control and bright LED display.
- 52 feet tall.
- Built-in timer.
- Same clicking sound, as the other model reviewed before.
Best Rated Cheap Clip Fan
Weighing in at just under 2lbs and with 6” fans, this fan offers very decent performance at a reasonable price. The fan has two speed settings which users can toggle between by moving the switch at the back of the unit.
On “high” speed, the unit can produce an impressive 306 CFM and 2350 RPM speed. This is more than adequate for 4×4 grow tents.
While not designed for use in grow tents, the mounting clip extends to a width of 2” meaning that it can fix securely to most tent poles.
But, the fact that this fan does not oscillate and its range of motion is fairly limited may make this fan best suite for a small grow tent.
- Easy to mount and operate.
- Adjustable tilt.
- Very light readily portable.
- Some users report issues / breakage with the clip.
Best Inline Fan Reviews
Let’s take a look at some suitable models of inline fans. This can be used for exhaust as well as intake, as you need it. The following are the best fans on Amazon designed to suit a variety of needs and budgets…
Best Overall Inline Fan
As the name suggests, this unit is built with power in mind. Delivering 2460 RPM and 190 CFM this entry from iPower is powerful enough to provide optimal ventilation for smaller to medium tents.
The build quality is very solid, composed of a durable ceramic coated housing and permanently lubricated bearings to ensure that it requires no maintenance on the user’s part.
It is fluted at both ends for easy attachment to ducting, while the composite fan blades are designed to keep noise to a minimum. Even at full speed, this unit remains below 50 db. That’s a little louder than rain on your window.
However, because the fan speed settings control is sold separately, this device may be a little too powerful if your tent is too small.
- Very powerful.
- Sturdy and durable.
- Fan speed control sold separately.
Best Quality Inline Fan
This active air inline fan from Hydrofarm is more than adequate for use as an exhaust fan. Moreover, because it’s made by Hydrofarm, you know that it’s designed and built with the needs of growers in mind.
This unit comes equipped with everything you need to mount and the ceramic coated green housing has two sturdy brackets in either side for hassle-free fixing.
And the 400 CFM output should be perfectly adequate to meet the needs of even large grow tents. However, those wanting to reduce fan speed will need to invest in a separate control unit.
While there are others on this list that offer similar performance for a slightly lower price, this unit is reassuringly robust, sturdy and well built from UI recognized components.
- High power.
- Made from UI recognized components.
- Thermally protected motor and ceramic coated housing.
- Permanently lubricated bearings.
- Some users report that the unit is louder than advertised.
- Fan speed control sold separately.
Best Cheap Inline Fan
This inline fan offers robust performance despite its compact size, and the 100 CFM output is great for mini and small grow tents.
It comes with a 6 foot long pre-wired grounded cord which should be more than adequate to allow easy installation in most spaces.
Weighing in at just 1.7 lbs, you’ll find that it’s easy to manipulate to minimize bends and turns in your ducting.
Although some users report a variety of issues with this model, the build quality and output capabilities make it ideal for use as an inline fan that supplements your tent’s ventilation system. Plus, the 12 month warranty attached to the unit provides a little extra peace of mind when running it.
- Budget-friendly. Good value for money.
- 1 year warranty.
- 6 foot cable allows for easy installation.
- Variable speed controllers are sold separately.
Best Performance Inline Fan
Delivering an impressive 440 CFM and 2450RPM, this unit has the power and performance to ventilate even large grow tents.
The sturdy yet compact build fits will into 6” vents, and its dual flanges allow for easy attachment to ducts as well as other equipment such as carbon filters.
At just over 10lbs it may not be the lightest entry on our lists, but the attached mounting bracket makes for easy fixture to your walls or ceiling.
There are many systems in place to muffle sound, reducing the noise emitted to around 40dB. If, however, you need further noise reduction, this unit can also be easily fitted to a silencer.
One of the main advantages of this unit is that it comes with a variable speed controller attached.
- Smooth and quiet running.
- Built-in variable speed controller.
- Good build quality and highly durable.
- Easy to install.
- Some users report variable speed may not make much of a difference.
Best Inline Fan For High Moisture
This duct inline fan from Tjernlund offers an impressive output of 460 CFM. Designed for use in high-moisture areas, it’s a great investment for when humidity is an issue.
At 10lbs, this unit is hardly a lightweight, although it comes with all the fixtures and equipment that you need for easy wall or ceiling mounting.
Designed with energy efficiency in mind, this unit operates at 120 volts / 125W with a maximum current of 1.1 amps.
Although it is designed to operate fairly quietly, the unit also comes equipped with a strip of vibration isolating foam. This allows for a better fit upon installation, and minimizes any vibrations.
- Energy efficient.
- Sturdy build.
- Assembled in the USA using mostly US sourced parts.
- Some users report issues with customer care.
- Fan speed control sold separately.
How To Calculate CFM For Inline Fans?
When ventilating your grow tent, you need to know how much fresh air must be provided to ensure healthy growth for your plants.
Fortunately, there is a formula that allows you to calculate the proper Cubic Feet per Minute (CFM) necessary to ventilate your tent.
1. First let’s find out the tent’s volume
While your grow tent may vary, we’re going to use a 4×4 foot grow tent with a fairly typical 8’ height as our example.
We multiply 4 (width) x 4 (depth) x 8 (height) = 128 ft3
2. Base CFM
Your inline fans should, ideally, replenish the who volume of air in your grow tent once every two to three minutes. So:
128 ft3 / 2 minutes = 64 CFM
That means you need to exchange 64 cubic feet of air per minute in order to properly ventilate your 128ft3 grow tent.
We will call this your base CFM.
3. Factoring In Ducts, CO2 Filters And Accessories
Now that you’ve got your base CFM, you also need to factor in your accessories such as your ducting, grow lights, and your carbon filter or silencer (where necessary).
These can all affect how hard your fan needs to work to achieve the perfect growing conditions.
For instance, any sharp bends in your ducting will significantly reduce airflow efficiency. A 90 degree bend can reduce airflow by up to 60%! Even a bend of 30 degrees will result in a 20% loss of efficiency.
Throw in another 60% if you’re using a carbon filter to neutralize odors coming from your tent (like if you’re growing in a stealth grow cabinet).
You can see how these will impact your base CFM:
|Accessories||Effect on CFM|
|LED grow lights||20%|
|HID grow lights||50%|
|Ducting 30º Bend||20%|
|Ducting 90º Bend||60%|
If we only had LED grow lights, a CO2 filter, and a few bends. Our final CFM formula would be:
64 (base CFM) x 1.2 (led lights) x 1.6 (carbon filter) x 1.9 (bends) = 233 CFM
Now you need to find an exhaust fan that can output this much CFM, as per your own grow tent and accessories needs.
Things To Consider Before Buying The Right Grow Tent Fans
Now we know why it’s so important to have a grow tent fan and how hard you’ll need yours to work depending on the size of your tent and accessories used. Most grow tent setups will do fine with a 6 inch duct fan. But before you start shopping, you’ll also need to consider…
The more control you can assert over your growing environment, the better. So we recommend that you either get a fan with adjustable speed settings, or (in the case of most inline fans) get them separately. This way you can experiment with settings to get the perfect air flow, humidity and temperature.
You also need to think about how accessible the dial / buttons will be for you from where your fan is positioned. Some oscillating fan models even come with a remote control so you can operate them from outside your grow tent.
Head Adjustment And Movement Of Clip-on Fans
You need to be able to control the oscillation of your fan to make sure that you get good overage of your growing space. Again, the more control you have the better. Most fans will oscillate from left to right, while some advanced models will have more complex figure 8 motions for superior air circulation.
You should also be able to tilt and adjust the head of your fan to get the air movement just right so that your plants’ stems get a good daily workout.
Your grow tent needs to be a stable growing environment for your plants. But it also needs to be safe for your plants and anyone with whom your share your living space.
You can choose a fan that is ETL listed and CETL approved. This means that it is made with safer parts and a higher quality build.
What Kind Of Duct Do You Need?
It’s very likely that you will also need ducting along with your inline fans.
We find that flexible aluminum ducting is a great choice for use with a inline fan setup. It’s easy to install and budget-friendly.
Although those with larger tents may prefer to use insulated aluminium ducting or a heavier duty duct if their budget permits.
Remember that smaller ducts create a greater airflow resistance, and longer ducts with more bends will also reduce airflow.
How Do You Manage Fan Noise?
Because you need a high-powered fan to ventilate your grow tent, you can expect some noise. But, there are ways to mitigate this so that your growing is more discrete and unintrusive.
Choose a fan with speed controls and a CFM rating 25% higher than your needs, this way you can run it at a lower speed making less noise.
Most of the inline fan models reviewed come with noise reducing features. But you can also attach a silencer which will dampen your intake fan’s sound (although, again, you’ll need to build this into your CFM calculations).
What Size Fan Do I Need For My Grow Area?
When you start researching fans for your grow tent, you’ll likely notice a huge variation in size. Most oscillating fans are anything from 6” to over 20” in diameter.
For most tents a 6” blade will usually give you the performance you need, for a up to a 4×4 grow tent setup. Keep in mind that when blades get larger, you may have to face a trade-off between performance and portability and space.
How Do You Hang A Fan In A Grow Tent?
Some grow tent fans come with a clip-on accessory so you can attach them to the tent’s poles easily, and in a really good angle.
If you don’t have one of those clip-ons, you’re going to have to get creative. Everything from a cord to duct tape will help, just make sure it doesn’t come in contact with anything else inside and you’ll be fine. Other than that, your best bet is going to be a tower fan.
Final Thoughts On The Best Fan
When it comes to grow tent fans, those looking for a freestanding fan will be more than satisfied with Seville Classics UltraSlimline.
If instead, you’re looking for a clip-on, the Vivosun Oscillating Clip-on fan offers good performance and features at a small cost.
When it comes to inline fans for your grow room, the iPower 4 Inch 190 CFM Inline Fan really hits the sweet spot between performance, quality and price.