Hon&Guan 4 Inch Inline Booster Duct Fan with Speed Controller - 130 CFM Airflow with 6W Ultra-Low Power and Low Noise

Definitely made a difference in the room. Easy to install and works great. It runs quiet until you put it in the duct, then it becomes louder. Worth the noise to cool the room down.

This is a small but powerful exhaust fan. I am using it in a retrofitted storm shelter that is now a small home workout gym. The exhaust fan works great to create a flow of fresh air from the entrance through the fresh air pipe that was built into the shelter. The speed control is a great feature. I rarely have to turn it up past the 50% mark to get the flow I want. The long power cord is also nice to have. I would note that the power cord is on the side, so take that into consideration on how you installing this fan.

Good fan, low power consumption but plenty of air moved. At 1/2 speed it uses about 19 watts with 12 volts at the DC plug. Don't care for the nonstandard controller box plug, was hoping for standard 5521 plug in case anything happens to the controller. It's a good fan, not as quiet as I wanted but it'll do for what I need.

Easy to hook up and works great. Good build quality and value for the money.

I got this to use with the enclosure for my laser engraver/cutter when the original fan just couldn’t keep up. And the original fan was great when it worked, powerful, but LOUD. It was louder than the whole laser setup. I had a hard time finding something as powerful as my 7800rpm fan, so was thrilled to find this one that can be set for up to 9000rpm. It is so much more powerful and still manages to be quieter than the original fan. I also find the price to be quite economical considering the benefits. Wow.

I tried another auxiliary single-speed duct add-on brand from Menard's that did not provide a respectable increase in flow. Unlike the other model, this variable-speed blower fan is more powerful, allowing me to set it at 50% with better airflow. The unit is a bit smaller in outer diameter (OD) than the inner diameter (ID) of my new 6-inch duct section, so I sealed the gap with a thick, metallic duct tape.All of these duct blowers add noise to the home, same as a window AC unit would. Expect to hear it. The duct fan sound does travel through the ductwork. I operate it only when it is needed to cool the room. I use a wi-fi power plug (and phone App) to power the blower on/off --- so I don't have to travel to the basement to deactivate it.

So I tried the hon&gaun, ac infinity raxial s6 and ac infinity cloud line pro s6. The hon&gaun definetly moved the most air for the money but it was the only one that I could here the motor running both standing next to it and at the end of the vent over 20 feet away even running only 40%. But even at 40% it still moved a lot of air and there was not too much turbulence so the air noise was minimal but motor noise was loud. I really don’t recommend this unless it is somewhere we’re the noise doesn’t matter. The ac infinity raxial was the opposite, a bit more money, moves far less air, the motor is silent but the lousy impeller creates a lot of turbulence creating a lot of air noise that is mainly heard at the end of the vent. Last was the ac infinity cloudline pro, it’s far more expensive but far superior, moves lots of air, motor can’t be heard even standing right next to it and the air flow is smooth and quiet. It also offers optional WiFi controller that is very easy to use, can control up to 4 fans which can be controlled by your phone, by set speed, schedule, atmospheric pressure readings, temperature or humidity. This allows you to put the probe in a vent and have the fan only run when ac, heat or humidifier are running.

Got this to vent resin printer fumes out the window. After messing around with it a bit it seems like it's up to the task.[UPDATED REVIEW 5/5/24]To stress test the fan a little, I left it by the window for 2 days, running non-stop at half power. Not exposed to direct sunlight or rain, on a level surface, etc. Normal working conditions. The fan eventually developed a rattle, like the fan is unbalanced or something. The rattle comes and goes. It's still quiet enough that the hose and enclosure mostly muffle it, but it's definitely concerning, and disappointing considering the good first impression it gave me. Maybe spend the extra 2 bucks on a metal exhaust fan instead, assuming those are sturdier.[CONSTRUCTION]This 4-inch inline fan is made of lightweight plastic, including the blades. Its tough not to be snarky and say this is basically a glorified computer fan, but that's the impression it gives because of all the plastic.The housing is sturdy though, it won't flex unless you're cranking down on the hose clamps at the ends (hose and clamps not included).This is actually one of the nicer products I've bought from Chinese manufacturers, it doesn't have that worrisome "cheap" feeling.If the plastic is a dealbreaker for you though, there are def more options in the same price range that have a metal housing instead, with varying CFM.This unit comes with a stepless dial-like controller to adjust the fan speed.There are no guards over the fan blades so don't stick your fingers in there, and don't leave it out for curious pets to play with.[NOISE]This fan can be quiet and noisy depending on the power level. When set somewhere between 45%-90% power there's an underlying mechanical whine. It doesn't sound like anything is loose or broken, it's more like the sound a jet turbine naturally makes as it ramps up in speed. I actually think it sounds cool, but I can understand why some people don't like it.Without the whine it simply sounds like a strong computer fan. I could sleep with it in the room, but maybe not at full speed.Playing with the speed controller is almost therapeutic. Don't bother with fidget spinners, get one of these fans instead![IN USE]I used this to ventilate a small resin 3D printer enclosure, and the 130 CFM Hon&Guan claims for this unit is more than enough for the task. I can set it to under the 40% power mark (where the mechanical whine starts to be noticeable) and it's still effective. I have a short hose though, if you're running a hose across the room you may need more power, or even a second inline fan. (There is a 6-inch version of this fan available if you need a lot more CFM.)I left it running at max power for a few minutes and haven't noticed any hot spots on the fan housing or controller, but I will keep checking on that.If you're using this fan to vent fumes, VOCs, etc., be sure the air you blow out the window isn't being blown back in by the air outside, or getting sucked back in through a different window haha. Also maybe consider putting some netting over the exhaust end to keep bugs from getting in when not in use.Another tip, try to install the fan as close to the window as possible. What you want to do is have the fan pulling air out of the hose/enclosure, not pushing it through. Pulling air prevents the polluted air from escaping from any leaks in your ventilation system, while pushing air through the hose will push it out of all those leaks along the way.[RECOMMENDATION]This is one of the cheapest and most streamlined options for resin printer ventilation on Amazon, and thankfully it works great. I will update this review if I find any long-term issues.