The Ultimate Inline Fan Battle: Which Fan Takes The Top Spot?

Growing indoors requires three primary investments: a grow tent, grow lights and an exhaust system. While grow tents and LED grow lights get all the attention, the inline exhaust component often gets ignored. Perhaps grow tent fans aren't as flashy as LED grow lights, but we'd argue they are just as important. If you are setting up a new grow room or revamping an old one, it's time to look at the newest in grow room fan technology.

Like we battled LED Grow Lights in 2020, we are now turning our attention to a Grow Tent Inline Fan Battle. If you are shopping for a new inline fan, get started with the following deep examination of four popular options. 

What is the quietest grow tent fan? What is the cheapest? What is the best grow box fan for spaces that need higher CFM? Based on several key characteristics, we determine which grow tent fan comes out on top with all categories considered.

Comparing Popular Grow Box Fans

Stepping up to the plate for this battle are four popular grow tent fans:

These four grow tent fans are all appropriate for small to medium scale indoor grows. What's more, they are all within an affordable price point for the novice grower or a larger scale, professional facility. 

The following Grow Tent Fan Battle covers four different categories, which are the pivotal points along the decision making journey decision making:

  • Price point
  • Noise
  • CFM
  • Energy efficiency 

While no specific fan won in all four categories, but the Vivosun and Cloudline S6 came out on top. 

....And spoiler alert, only one of these brands had the quality and customer reviews to make it to the top: AC Affinity Cloudline S6. If you are looking for the best grow tent fan on the market, we'd highly suggest checking out the specs on this small, quiet, and powerful exhaust fan. But we are getting ahead of ourselves. The battle begins!

Let's Battle for the Title of the Best Grow Tent Fan!

Unless otherwise stated, the four grow tent fans we've put to battle are 6" with a speed controller. Of course, there are always add-ons for the indoor grower, like carbon filters and humidity controllers, but to keep the comparison fair, we've aimed to battle apples to apples (instead of apples to oranges). 

Price Point

  • Best Price:  Vivosun 6": $69.49
  • Second Place: Cloudline S6 : $129.99
  • Runner Up: Can-Fan Max-Fan 6": $171.00
  • Last Place: Vortex S-Line Ultra Quiet 6": $198.00 (plus add on Speed-Controller)

While speed, CFM rating, and features are always critical, ultimately, any decision in the grow room comes down to price point. When it comes to grow room fans, the most affordable option is hands down the Vivosun 6" Inline fan. At only $69.49, it is the cheapest known-brand on the market and perfect for newbie growers. But, as we shall see, the brand sometimes doesn't hold up over time, at least according to many one-star customer reviews.

In second place comes the Affinity Cloudline S6 at $129.99. The higher price point is understandable considering the improved DC motor, which improves speed control and reduces noise over the conventional AC powdered motors. Plus, for only $30 more, the Cloudline T6 model comes with additional features, like the temperature and humidity controls, both well worth the added value for peace of mind. 

Both the runner up and the last place options, Can-Fan Max-Fan and Vortex S-Line, are closer to the $200 mark. But neither comes with any notable features which make the added costs worthwhile. For example, the Can-Fan model only has three-speed options, and the VortexS-Line requires you to buy the additional controller, which is another $30.

If the price is the only concern, The Vivosun wins this round, with the Cloudline S6 a close second.

Energy and Efficiency

  • Highest Efficiency: AC Affinity Cloudline S6 
  • Runner Up: Can-Fan Max-Fan 6"
  • Worse in Class: Vivosun 6" and Vortex S-Line 6"

When it comes to profitability — operational expenditures matter. While most growers pay attention to their grow lights' efficiency, many forget that the grow fan is a power-hog. Fans are always running, which can end up adding up to significant charges on your energy bill. If energy costs matter for your operation, you'll want to choose a grow room fan based on its energy efficiency. 

AC Affinity delivers the highest efficiency out of the four fans compared in this battle. The reduced energy consumption is thanks to the DC-powered motor (but don't worry, it also comes with an AC power adaptor). The DC-component also helps reduce excessive noise. The average power draw on the S6 model is 38 watts (maximum is 64 watts).

Can-Fan Max Fan has very similar efficiency to the Cloudline, ranging in max wattage between a high of 75 watts (at the highest speed setting) and 53 watts at the lowest. The Can-Fan 6" has specially engineered 3D blades on the impeller and stator, which the company claims improves the efficiency by 50 to 100 percent over the competition. Considering the Cloudline Affinity model outperforms the Can-Fan model, this claim may be a slight exaggeration.

The Vortex S-Line 6" inline duct fan doesn't clarify much in terms of efficiency, only indicating its power draw is 70 watts at 120v. But with a speed controller, there will likely be a significant variation on this number as it doesn't indicate speed, maxim, or average in the specs. With few details on the maximum and average power draw, this fan is a difficult sell for growers concerned about energy costs.

The specs on the Vivosun 6" model are much less efficient. According to the technical specs, the Vivosun pulls 135 watts, but the specs also don't clarify between average and max. Either way, this is significantly higher than the Cloudline model.

Noise and Decibel Rating

  • First Place: AC Affinity Cloudline S6 
  • Second Place: Vortex S-Line 6"
  • Last Place:  Vivosun 6"
  • No Data: Can-Fan Max-Fan 6"

Perhaps the biggest concern for the indoor grower when it comes to inline duct fans is noise. Inline fans are not known for their silence. Therefore, most grow-room specific fans, like those compared here, will promote their technology's quiet nature. Let's see how they stack up against each other.

Cloudline S6 has a noise rating of 32 dBA, which sits somewhere just above a loud whisper on the decibel scale. As per the technical specs, this model's quiet nature is thanks to a mixed flow design and a PWM-controlled EC motor. 

Vivosun has a noise rating of 50 dBA, comparable to the hum of a refrigerator or a quiet conversation. Although for many growers, this may seem like an acceptable level of noise, it's the details hidden in the reviews that are worth noting. Across several retailers, reviewers pointed out that the Vivosun model gets much louder over time. With so many reviews saying that the fan gets significantly louder within a few months, you'll want to consider this as a stealthy indoor grower.

Now, on to the Vortex S-Line, which has a design with double-insulated walls for noise-reduction. Unfortunately, there are no specs on the decibel rating for this model. One reviewer did perform his own measurements and recorded 50 dBA for the Vortex S-Line fan. Similar to the Vivosun.

Unfortunately, there is no decibel rating for the Can-Fan Max-Fan. Only vague claims about "optimized mixed-flow are quieter than comparable fans." 

Considering two out of the four brands don't list any noise rating, and a third has noise issues popping up throughout the reviews, the AC Affinity is the clear winner. 

Airflow (CFM)

  • First Place: AC Affinity Cloudline S6 and Vortex S-Line 6"
  • Second Place:  Vivosun 6" (with warnings based on customer complaints)
  • Last Place:  Can-Fan Max-Fan 6"

One of the fundamental aspects of ventilation and airflow within a grow tent is the CFM or the cubic feet per minute of air exchange. Ventilation systems for grow rooms and grow tents must exchange air at least once every three minutes. To calculate what size fan you need with what CFM rating, you'll need to calculate CFM. We've covered how to do this in detail here.

Of course, each of these inline fans will have additional components (filters and ducting), adding drag into the system. But for the sake of comparison, we are assuming each of the fans below is used in isolation.

The Cloudline S6 model has a rating of 351 CFM, which would be suitable for a 4'x 4' Gorilla Grow Tent with two lights. 

The Vortex S-Line Ultra Quiet Fan 6" grow tent fan has a minimally lower CFM, with a 347 rating. This would also work within the same grow tent example as above.

The Vivosun 6" model has much greater capacity, with a notable 440 CFM. But again, the comments say it all. Several reviews noted that within a few months, their fans stopped working altogether, began rattling, or in one case, started smoking.  

Finally, the Can-Fan Max Fan 6" option has the lowest rating, at only 330CFM. Within the grow tent example given above, it would no longer be suitable. Although it would work within a smaller tent or with a single grow light.

Final Decision: The Best Grow Tent Fan Cloudline S6

When we compared noise, efficiency, airflow and price, there were two top contenders: the Cloudline S6 and the Vivosun. Both the Vivosun and the AC Affinity Cloudline S6 inline duct fan came out with a few wins each. 

But, and this is a big caveat, the Vivosun doesn't seem to hold up over time. When customer reviews come into play, the Vivosun fails to impress.

Yes, it's cheaper. And yes, it has better CFM. But according to the reviews (across multiple websites), the Vivosun is likely to get louder within a few months. In some cases, it seems to break down altogether, and it may get to the point of smoking. 

When we consider customer reviews in to the picture, the Vivosun is worrisome. You may need to replace the Vivosun on your own dime shortly after install. What the Vivosun reviews tell is that cheaper doesn't mean better. 

Therefore, we conclude that the Cloudline S6 is the best grow tent inline fan. It comes with none of the serious concerns of the Vivosun. It is the winner in terms of noise reduction and energy efficiency. While it may be only second place in terms of price point, at least you won't have to replace it after a few months. For indoor growers, we think quality and quietness trumps affordability.

Click here to see more pictures & information about the Winner: Cloudline S6 Inline Duct Fan w/ Adjustable Speed Controller







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