AC Infinity CLOUDLINE PRO S4 Quiet 4 Inline Duct Fan with Speed Controller EC Motor Ventilation Exhaust Fan

This is my third, and likely last, exhaust fan I've bought for a project. I wanted an exhaust system for our cat's litter box cabinet so that it would create a small amount of negative pressure and pull the bad odors outside. This fan is absolutely perfect in every possible way and has far exceeded my expectations. I arrived at this fan, after purchasing two others that were just too loud, as the noise seemed to bother the cat. I installed 2" PVC in the wall behind where the cabinet is, because I needed something small enough to fit. I then had a 90 degree elbow coming out of the wall, through a cover plate and then going into the back of the cabinet. In the attic, I installed a 2" to 4" duct adapter onto the 2" pipe, ran 25' of flex duct to this fan, and then another 16' run of duct to the roof vent. While the first two fans where very noisy, even at the lowest speeds, this one is virtually silent. I'm running it on level 2 and cannot hear anything inside the cabinet or in the house. Since I'm restricting the intake to only 2", anything above level 2 would likely just be a waste of power. This setup is working perfectly and creates more than enough exhaust to do the job and it does it in silence. The prior fans moved the air ok but had a really annoying hum that could be heard through the ductwork and also inside the house through the insulated ceiling. I hear nothing with this one. In addition to the above, the fan is rock solid and came with EVERYTHING one could possibly need to install it, including hose clamps. It's almost overkill but shows attention to detail. It also came with a very nice instruction book (yes, it's a substantial book) with detailed instructions on every aspect of installation and operation. The speed controller is very nice and easy to use. I just set it to my desired level and forget it. It will remember its current setting and resume after a power outage. This fan cost a bit more but is absolutely worth every penny paid. The difference in quality and quietness cannot be matched. I could not be happier, cat is happy, and we have an odor-free home. Read more

I purchased the AC Infinity CLOUDLINE PRO S6, 6” Inline Duct Fan with Speed Controller to help keep my miner room cool, and it has exceeded expectations. The EC motor is both powerful and efficient, and what surprised me most is just how quiet it runs, even at higher speeds. Installation was straightforward, and the included speed controller makes it easy to adjust airflow as needed. Running multiple miners can heat up a room quickly, but this fan has made a huge difference — it keeps temps under control without adding a lot of noise or power draw. The build quality feels premium, and I can tell it’s designed to run continuously without issues. ✅ Pros: Very quiet operation, even at high speeds Strong airflow to keep miner room temperatures down Speed controller included for precise adjustment Efficient EC motor saves power over time Solid build quality, designed for 24/7 use ❌ Cons: Higher upfront cost compared to budget inline fans Speed controller cable could be a little longer 💡 Tips: Use insulated ducting to further reduce noise. Mount the fan with vibration-dampening straps for an even quieter setup. Pair it with a temperature or humidity controller for automatic adjustments. Clean the fan and ducts periodically to maintain peak airflow. Bottom Line: The CLOUDLINE PRO S6 is a top-tier ventilation fan that’s perfect for high-demand environments like mining rooms, hydroponics, or grow tents. It’s quiet, efficient, and powerful — exactly what you need for reliable cooling in a 24/7 setup. Read more

I'm very impressed and pleased with this 6" booster fan from AC Infinity. The user reviews were very helpful in my decision to purchase this blower. Especially the most-recent reviews tend to give a better picture of the item's performance. NO REGRETS! It was very fast shipping in a very well packaged box!!! You can tell when a manufacturer takes pride in their products just in the unboxing. Everything was premium quality! Specifically, the blower design is exceptionally well-designed and manufactured. The user manual was very good. Do read the manual first! This duct booster/fan can be mounted virtually anywhere in a number of flexible ways. In my case, the blower had to mounted between rigid 6" steel duct pipes. You might opt for the ~ 3" rubber adapter sleeves. I didn't and wish I had. But I was bent on getting the unit installed with what materials I had on hand. Not cobbled though! Anyway, if you must install the unit between two fixed pipes, first remove the blower proper from the main mounting bracket which incorporates the two IN/OUT adapter flares. Just loosen the two main banjo band clamps. You almost have to turn the screws all the way out before the bands can be pulled away. With the motor assembly removed, you can then mount the bracket sub-assembly to the ducts and secure that part of the set-up. Ingenious design that makes the rest of the assembly a "breeze", pun intended! Regarding the noise: I worked 35 years in noise & vibration control. There's no way this unit can be only 32 dB at typical or standard measurement locations. It must be rated such on the lowest speed. That said, the thing is still adequately quiet even at half-speed. And my basement bathroom is now toasty warm. Btw, I have this booster wired to come on only when the house HV blower comes on. It's nice that the digital blower control doesn't lose its setting. Everything on this huffer is top-notch and very well engineered. Read more