Best inline fan: How to choose duct fans for grow tents

Given that we recently talked about why grow tent ventilation is important - let’s take a look at inline fans. Inline fans, also known as inline duct fans are widely used in growing cannabis as well as other plants - so check out our guide below on how to choose an inline duct fan for a grow tent!

What is an inline fan

You’ve probably seen growers use fans before - in most displays growers will have a couple oscillating clip fans to move the air around and imitate wind. But what is an inline fan, and what is its role?

Inline fans are cylindrical fans which are introduced to your grow tent in order to create a healthy amount of airflow and bring fresh air to your plants. They also play a very significant role in controlling the temperature and humidity of your grow tent.

Inline duct fans are usually placed around the ceiling of your tent, and connected to ducting. Their primary use is to expel the heat and humidity outside of your tent so they won’t affect your plants in a negative way. Paired with carbon filters, inline fans provide your plants with the optimal growing climate while removing all unnecessary smells.

Inline duct fans usually come in 5 different sizes:

  • 4 inch inline fans
  • 6 inch inline fans
  • 8 inch inline fans
  • 10 inch inline fans
  • 12 inch inline fans

The inches represent the diameter of the inline fan - which is also one of its most important features. Keep in mind that some grow tents may not be able to fit larger inline fans.

The power of an inline fan is defined by the cubic feet (per) minute or CFM output it can generate. Most smaller tents don’t need a big CFM output, in fact 4x4 grow tents usually need an inline fan with a CFM of anywhere from 200 to 500.

Bigger tents will need bigger fans, which also increases their CFM output. Most 10-12-inch fans often have up to 1500 CFM or more. Larger inline fans can be used to vent complete grow rooms, however bigger grow rooms require industrial-type ventilation.


Best inline fan for grow tents

You might think choosing an inline fan may be easy, but how would you know if you got the best inline fan for your grow tent? Well, it has lots to do with the tent you plan on using.

Before choosing an inline fan - you ought to check the size of the duct ports on your grow tent. Most smaller grow tents (up to 4x4 feet) usually have 4 inch ducts, 6 inch ducts, or 8 inch ducts - or a combination of the three. Bigger tents - think 8x8, 10x10 and so on, usually have 10 inch ducts or 12 inch duct ports as they require bigger fans in order to move the air out.

AC Infinity inline duct fans have been almost unanimously accepted as the industry leaders in their field. Their products are just a step ahead of the competition in almost every aspect - they’re cheaper, quieter and have extremely high air output in terms of CFM.

With that being said let’s cover some of their inline duct fans, and see how they fare against other brands such as Vortex and Max Fan, and as of recently Spider Farmer!

4 inch inline duct fan

The best inline duct fan in the 4-inch size is the AC Infinity T4. It has the best cost to quality ratio by far as models from other brands are noticeably more expensive while just not offering the same bang for the buck.

The AC Infinity T4 as a temperature and humidity controller, both of which can be digitally adjusted through the controller which comes with the fan. The controller offers 10 speed settings, as well as manually adjusting the humidity in your grow space. It can also be used with the AC Infinity S4 model.

The S4 Model is mostly the same as the T4 model, however it lacks the humidity control feature. However - it does come at a discount due to having a feature less than the T4. These two fans are great picks for beginners growing in smaller tents, such as 2x2, 2x4 and 3x3 grow tents.

6 inch inline duct fan

Just like the 4-inch version, AC Infinity offers the best inline duct fans in the 6-inch size as well. The S6 and T6 are by far the best in their class. The S6 and T6 have an 8-speed controller and they come alongside with an instruction manual and all the hardware you’ll need to hang them up.

As we mentioned before - the Spider Farmer inline duct fans have been recently getting more and more popular. The Spider Farmer brand offers a very cheap bundle including the 6-inch inline fan, a carbon filter and all the ducting you’ll need for just $139.00

8 inch inline duct fan

The AC Infinity S8 and T8 would be our pick in the best 8-inch inline fan race - but instead of being repetitive, let’s talk about some other brands and see how they fair with AC Infinity

One of the more popular brands out there is Max Fan - with their Pro and Q series. The 8-inch Max Fan Pro and Q fans have a CFM rating of 863 and 785 respectively. Both of those are higher than the 740 CFM which the S8 and T8 can put out. However - the price difference between these three models is just not worth investing in the Max Fan models.

The S8 and T8 come in at $169 and $199 respectively - which $100 cheaper than the Max Fan Pro. You’d save a lot more than that by avoiding the 8-inch Max Fan Q Max which comes at a steep price of $465 and some change - definitely not worth the investment as it doesn’t even come close to what you’re getting with the AC Infinity models.

10 inch inline duct fan

In the 10-inch category, there are a couple of models which can create a bigger output than the AC Infinity models. However, they also use significantly more power, and cause comparably more noise.

10-inch inline fans are a great choice for venting bigger tents - such as the 4x8 and even larger than that. The S10 and T10 offer incomparable venting, and your plants will definitely love the healthy airflow and optimal growing environment these fans create. Both versions are capable of putting out over 1200 cubic feet of air per minute.

They are also noticeably cheaper than their competition - so the money and get yourself one of the AC Infinity models. The money you’ll save will come in handy when getting other parts of your grow kit, such as lights. Quality lights can be quite pricey - but that’s an investment that quickly pays itself off. You want the best 10-inch inline fan - you get yourself a T10 and you’re set for the foreseeable future.

12 inch inline duct fan

If you need to move serious amounts of air - look no further than the T12. This monster is capable of moving a whopping 1604 CFM. Just like the other, smaller AC Infinity models - the T12 and S12 come equipped with a controller.

Both versions can use the 8-speed manual controller, which utilizes the PWM technique - something we’ll talk a bit later. The S12 and T12 are the quietest 12-inch fans on the market. You’ll have a hard time finding a fan that big and fast, while creating almost no noise at all.

Other brands are just no match for AC Infinity in this category, because as time passes and they get more loose from spinning - they start creating more and more noise. So - let’s just leave it at that.

What are the quietest inline fans?

One of the main concerns when buying an in line fan is whether it causes noise or heat. AC Infinity S and T series fans are known to be some of the quietest inline fans on the market.

What makes AC Infinity fans truly the quietest fans on the market is that they are equipped with EC-motors which work based on the PWM (Pulse Width Modulation) technology. The PWM technology allows the fans to run smoothly without generating almost any heat or noise.

What is the most powerful inline fan?

One of the most powerful inline fans out there has to be the 14-inch Max Fan HO, also known as The Beast. Now - The Beast is by no means the best inline fan on the market.

It’s capable of putting out 3343 CFM, and requires a 240V power inlet. If you’re looking for the biggest, strongest fan, are you’re not worried about the sound it may produce, then give this beast a go.