Are you searching for the best fan for your grow tent? Grow tents are easy to set up and allow better control of the environment. For a successful yield, proper ventilation is crucial.
With requirements for specific temperature, humidity and carbon dioxide levels, cannabis is a plant of many needs. Luckily, these can all be controlled, to a certain extent, by choosing the best grow tent fan.
Selecting the right fan isn’t as straightforward as it may seem. Size, type, power, noise and other factors need to be considered before purchasing one. Don’t worry, this guide gathers all the information you need to make an educated purchase.
We’ve also put together a selection of the best fans for grow tents, to make your search easier.
Quick Answer: The Best 5 Fans For Grow Tents In 2021
What Is a Grow Tent?
Grow tents come in different sizes, and most are portable and reusable. The outside fabric is usually made of canvas, while the interior is covered with a reflective material for optimum lighting. Many are insulated, to maintain heat, temperature and humidity.
Some grow tents come fully equipped with lights and fans, while others require you to purchase these separately.
All types, however, should feature circular holes to install a grow room inline fan or duct. Many grow tents also come with metallic bars to be placed across the ceiling. These will be important when securing an inline fan.
Why Do You Need Fans in Your Grow Tent?
Ventilation is essential to the health of your cannabis. The best fans for growing weed even include useful accessories to make your growing life easier.
This video is a nice introduction to the benefits of using a grow tent.
Like all plants, cannabis needs both carbon dioxide and oxygen to survive. In a closed environment without any ventilation, CO2 levels will rapidly be depleted.
When using a grow tent, direct access to an open window isn’t always possible. This is where the best fans for grow tents come in.
Ideally an exhaust system should allow for 2-way air circulation. Fresh and cool air comes in, while the hot air goes out. The light breeze will also strengthen your plants’ stems.
Weed breathes. In a closed setup, humidity can accumulate. A stable airflow and controlled humidity levels prevent fungi, rot, mildew, mites or mold from developing and thriving.
You’ll want to aim for 40 to 60 percent humidity up to the final weeks. A proper exhaust system—and potentially a hygrometer—will help keep humidity levels under control.
Grow lights will raise the temperature in your grow room. This needs to be counterbalanced to avoid burning the leaves. Growers using high intensity discharge (HID) lamps should be especially cautious, as these lights emit a considerable amount of heat.
You should aim for a temperature between 70 and 85 degrees Fahrenheit when lights are on. When they’re off, the temperature can range between 58 and 70 degrees Fahrenheit.
Different Types of Fans
A variety of fans exists, and each type serves its own purpose.
An oscillating fan will move the air throughout your plants. They’re one of the most inexpensive fans available and will help you keep your grow tent cool and well-ventilated.
The best oscillating fan for a grow tent is often lightweight and can be positioned in different ways to ensure an even air circulation. For larger tents, several fans might be necessary.
They do not remove air from or inject it into your grow tent. Rather, they complement an exhaust system which doesn’t have the ability to move air around your plants.
The best fan for grow tents can be placed flat or mounted to your tent’s wall or ceiling using clips. Ideally, you want air to circulate above, under and between the plants.
Pointing the fans directly at the plant can cause wind burn; the leaves will curl up in a claw shape. Strong air movement can also cause damage to the stems, and should be avoided.
The ideal ventilation system should allow both the warm air to escape and fresh air to enter your grow tent.
The best inline fans for grow tent can either push air in or pull it out. To allow both, two fans will be necessary.
Outtake or Exhaust Fans
An outtake fan will act as a vacuum and push the old air out of your grow tent. The best fan for grow tents will constantly be removing existing air.
Not planning to install a separate intake fan? In that case, the intake hole should be at least three to four times larger in diameter than your outtake fan. An alternative would be to create more than one intake hole.
Intake fans have the opposite task. They draw fresh air from the outside and inject it into your grow tent.
Based on your preference and the size of your grow tent, many setups are possible. For any installation, however, flexible aluminum ducting and duct tape are necessary.
Outtake inline fans: The temperature is likely to be at least 41 degrees Fahrenheit warmer at the top of your tent than the bottom. For this reason, most hobbyists attach and secure the fan to the metallic bars placed across the ceiling.
Duct tape will hold the duct and the fan together. It then passes through the upper hole of your grow tent to the outside environment.
Intake inline fans: Installation should start from a source of fresh air, ideally a window. Ducting then directs the airflow to your intake fan and into your grow tent. In this case, the fan is often placed outside of your tent or right at the tent opening.
It’s worth repeating that intake and outtake fans are the same devices but used in opposite direction. Each will direct airflow either in or out of the tent.
It’s best to keep your duct in as straight a direction as possible. Every 90-degree angle curve loses about 20 to 30 percent of CFM (cubic feet per minute). This refers to the amount of air your fan can move, and is discussed in more detail below.
Fans with Carbon Filters
The best inline fan for grow rooms often come with a carbon filter. What is it — and do you need one?
Carbon filters have two main benefits. First, they remove impurities and airborne bacteria from the air.
Additionally, they filter odors from your grow tent. I’m not only talking about the nice fresh smell of a growing cannabis plant. Humidity mixed with heat, pesticides, and wet soil can create unpleasant smells.
They’re often cylindrical in shape and come with a fabric sleeve to place around the cylinder.
Carbon filters are simply attached to your inline fan—whether inside or outside your grow tent—using duct tape.
It’s not an essential purchase up front. Carbon filters can be purchased separately and added on to your fan at a later time if needed.
You might find inexpensive fans called ‘booster fans’. They’re used to help the air circulate and move along long ducts.
These types of fans are add-ons and shouldn’t be used as the main fan of a ventilation system.
What Is the Right Size?
When selecting the best fan for your grow tent, it’s important to consider the size of your growing space. A larger volume will need a fan able to ventilate and move more air. This is measured with a CFM rating.
What is CFM rating?
CFM stands for cubic feet per minute. It represents the volume of air that your fan can move every 60 seconds. Inline fan manufacturers should provide this information.
Calculating Your CFM Requirements
To calculate the CFM rating needed for your grow tent, here is a simple formula. Multiply the width, length, and height of your grow space (in feet). Then multiply this number by 125 percent (or 1.25).
The final number represents the CFM needed for your grow tent. That is, the amount of air the fan should remove per minute.
Why 125 percent? The additional 25 percent will give you some extra room. If you’d like to install HID grow lights or upgrade to a larger grow tent down the road, you should be covered.
Ideally, air should be renewed every minute. However, the air in your grow tent can be renewed every one to three minutes and still do its job.
If you have budget constraints, divide your CFM number by three. This will be the minimum CFM you’ll need. For example, if your CFM calculation was 180, you should aim for a fan with a minimum CFM rating of 60.
When it comes to CFM, bigger doesn’t mean better. The size of the fan doesn’t reflect how powerful it is or how much air it can move.
Adjusting your CFM
HID Light System
HID (high intensity discharge) grow lights can generate a considerable amount of heat. Some have air-cooled reflectors built in to limit the heat built-up.
With HID lights, it’s best to consider a fan with a higher CFM rating. How to select the best fan for your grow tent if you have this lighting? Add 5 percent if your HID lights include air-cooling reflectors, and 10 to 15 percent if they don’t.
If you’re using a carbon filter, add 20 percent extra CFM.
If you live in a hot climate, add an extra 25 percent CFM. For humid climates, an additional 40 percent CFM might be necessary.
When in Doubt
In general, it's best to aim for higher CFM than required. The best grow tent fans generally come with speed control devices to adapt the airflow as needed.
Other Things to Consider
Before discussing the best fans out there, here are a few more things to consider.
As we mentioned, the power of a fan isn’t determined by its size. So why is the fan diameter important?
Grow tents usually come with specific opening sizes to set up inline fans and ducts. Grow tent have holes that are usually either 4, 6 or 8-inch openings, and ducts will match your fan’s diameter.
When purchasing a fan, it’s best to ensure that the fan and duct will fit the diameter of your grow tent opening hole. If you’re unsure of the size, aim for 6 inches. Converters are available, to adjust the size if needed.
Powerful fans have a tendency to be noisy. Try to find a good balance between noise and power. Silent grow tent fans are always preferable. This is especially true if you keep yours in or near your living space.
It’s best to select fans that have been approved, listed or certified by formal bodies. They’ve been thoroughly tested and ensure a certain level of quality. Here are a few popular ones.
- ETL listed: Fans comply with the North American safety standards.
- UL (Underwriters Laboratories) or ULC (for Canada): Test electronic products to ensure their safety.
- CSA (Canadian Standards Association): Canadian group, recognized in the United States and used worldwide.
The best inline fan for grow tents might include accessories, such as a speed controller, or humidity and temperature devices. Some even come with a timer to control your plants’ day and night cycles.
These may come at a higher price point. They can, however, save you some precious time when trying to reach an optimum environment for your plants.
The Best Fans For Grow Tents
Now that we know what to look for in a fan, let’s go into detail of the best ones available.
Best Overall - AC Infinity CLOUDLINE T6, Quiet 6” Inline Duct Fan
This inline fan comes with quality, power and convenience, making it one of the most popular fans.
The fan is compatible with any 6-inch duct and carbon filter. Featuring an airflow of 351 CFM, it should work with most grow tents.
It also comes with an intelligent controller that’s easy to use, and designed to make your life easier. In one single screen, you’ll be able to monitor, select and modify the speed of your fan, from 10 different setting options.
The screen also displays the temperature and humidity of your grow tent. Finally, the timer allows you to set a specific number of day and night hours in your tent. This aspect is crucial when it comes to optimum growth.
This inline fan has been designed to emit very little noise while being energy efficient at the same time.
This kit includes two duct clamps and the needed mounting hardware. If you’re adding other fans later, they can be set up on the same smart controller device.
- Low noise—32 dB (on lowest speed).
- 10 different speed settings available.
- Displays temperature and humidity.
- Timer built in.
- Energy efficient.
- Alarm built in.
- Can share the same power source and controller with another fan.
- The smart controller can be difficult to mount on a tent wall, and tape might be necessary.
Runner Up - 6" Inline Fan - 395 CFM Exhaust Duct Fan
This 6-inch fan has a CFM rating of 395, which should allow proper intake or outtake airflow in a regular grow tent and under normal lighting conditions.
The speed controller displays three settings: low, medium, and high. This won’t only allow you to reduce the airflow when needed, but also the noise level and your electricity bill.
Made of ABS plastic, this inline fan comes in three parts, with a removable central section. This allows for easy cleaning and maintenance. To remove it, simply pop the buckles and spin the central piece in a 30-degree angle. This should do the trick.
This fan will operate in temperatures up to 140 degrees Fahrenheit, and includes thermal protection. If your grow room accidentally reaches 130 degrees Fahrenheit, it shuts off automatically.
- Speed: 2400 RPM.
- Comes with a 3-level speed controller.
- ETL listed.
- One year warranty.
- Comes with mounting brackets.
- Lightweight—5.5 pounds.
- Easy to install.
- Noisier than other fans—45DB.
Best Fan for Small Tents - iPower 4" inch INLINE DUCT FAN blower
This 4-inch fan might be ideal for smaller tents, and when growing only a few plants. With an airflow rating of 190 CFM, this should be enough power to renew the air within a couple of minutes.
Worried that you might need a stronger fan down the road? This versatile fan can have many uses. It could be installed to boost airflow down a long duct. Alternatively, you can use it around the house for improved air circulation if you eventually upgrade your grow tent fan.
Are you just getting started and need to buy all your growing equipment at once? Limited in your budget? This fan shouldn’t represent a big hit on your wallet.
For a small fan, it has some nice features.
It has been designed to reduce the number of vibrations. The lubricated bearing makes maintenance a simple and quick process. It requires minimal assembly, and can be used straight out of the box.
If you’re looking for other fan components, such as ducting or carbon filters, these can be purchased separately.
- Speed: 2460 RPM.
- High-quality composite fan blades.
- Simple fan, easy to set-up and install.
- Easy to clean.
- Loud compared to the power provided—48 dB
- Heavier than other fans—6.2 pounds.
Most Complete Package - PrimeGarden 8'' Inline Fan Carbon Filter Ducting Combo
This fancy kit comes with everything needed to set up proper ventilation in your grow tent. This durable fan has been thoroughly tested and is UL certified.
Featuring a 720 CFM rating and 8 inches in diameter, this fan is ideal for larger tents. It comes with a 3-level fan speed controller—low, medium and high. This kit even comes with high-quality silver ducting.
The included screen can either be hung or placed on a flat surface. It allows you to monitor the temperature and humidity level within your grow tent.
This kit also comes with a carbon filter included. This will remove any unpleasant smells and filter out potential airborne bacteria from your grow space.
- Includes a hygrometer and thermometer—batteries are also included.
- 15-minute cycle timer.
- UL certified.
- High CFM power.
- A carbon filter and fitted sleeve are included.
- Three speed settings.
- Clock and calendar functions.
- Two elastic ropes—double silver layered—and steel clamps included for easy setup.
- Short carbon filter life expectancy of up to 1.5 years.
Best Oscillating Fan - Tornado 16 Inch Digital Wall Mount Fan
This 16-inch diameter fan features strong ABS blades, and speed can be adapted using three different speed settings.
A remote allows you to change your fan’s mode—normal, sleep, nature—from a distance. If you're installing several oscillating fans from this manufacturer, they can all be conveniently controlled through this one single remote device.
To ensure your plants get proper and equal ventilation, this fan can move through 120-degree horizontal oscillation. Vertically, you can tilt the fan up to a 60-degree angle. It also comes with a timer, with 30 minutes to 7.5 hours increments.
The remote control makes it particularly easy to use. This is especially handy if you’ve installed the fan in a section of your grow tent that is difficult to access. The remote can even be operated from 20 feet away. Note that batteries aren’t included.
Easy to follow directions makes assembly easy. It shouldn’t take more than five minutes before your plants can enjoy some fresh air. If assembled improperly, the fan will automatically shut off.
- Quiet inline fan.
- Motor is covered by a 5-year warranty.
- ETL listed.
- Easy to assemble.
- Study steel construction.
- Durable mounting bracket included.
- Users report more noise than expected.
Proper air circulation is necessary for any cannabis grow space. Luckily, grow tents allow better control over temperature and humidity, making your ventilation job easier.
Whether you’re looking for an intake or outtake fan, or simply to boost existing airflow, a fan will meet your needs. The best fans for grow tents might represent a larger investment, but will be worthwhile in the long run.
I personally prefer the AC Infinity CLOUDLINE inline duct fan. Not only is it sturdy, but it also contains all the needed accessories to save time while creating an optimum growing environment.