4 inch in-Line Fan 165 CFM

It was easy to open up the fan's electrical box to remove the electrical cord and hard-wire it with 12-2 Romex. I'm using it as an in-line bathroom fan, and have it mounted up against the joists underneath the platform of my yurt. My only complaint is that the metal mounting arms that are included are VERY sharp on their edges, but are otherwise perfect to attach the fan to a short piece of 2x4; I then screwed the 2x4 to the underside of the joists. No vibrations or rattling -- I have no idea why other reviewers are complaining about this. In fact, turned on full power, you can barely tell it is operating. I suspect the noise complaints come from folks who are using uninsulated plastic flex duct, where the ridges catch the air and cause turbulence within the duct. I was initially going to use rigid metal duct but then I chose to use pink fiberglass INSULATED plastic (HDPE) duct because of convenience, which I ran in my wall and out under the joists. I suspect the insulation absorbs a huge amount of noise that you'd otherwise hear from plain old plastic duct.As far as fan controllers are concerned, Amazon and the manufacturer push you toward a wall-wart style controller. Because my use for this fan is as a fixture, there was no way I was going to use one of those Active Air controllers, because its a wall-wart, no matter how good it it. I was THRILLED to discover that this .95 Amp (max) rated fan is controlled PERFECTLY by a Lutron Skylark SFSQ-LF fan controller/light switch (which Lutron states only works on "solid state" fans, whatever those are). I tested for humming inside, before mounting the fan, so I could hear well. There was NO humming from the fan at ANY of the three speeds offered by the Skylark controller, though the two speeds other than full blast are a little slow for my needs -- in hindsight I could have gotten away with a simple light switch. I might use the middle speed to circulate air if I'm out of town.Very happy -- this was a great value for the price.

I have a unique situation with a PC that generates a LOT of heat. The room temperature can reach 95 degrees on a hot day, small room with a southern exposure. I modified the PC case with a four inch duct collar and attached the input for this fan to it. The fan output is vented outside. It's been running 24/7 for two weeks, now, with no problems. The room temperature never gets over 85, even with bright sun and 100 degree outside temps. As a bonus, the internals of the PC have dropped about 20C as well which will add lots more life to them.There is some noise involved but it is more the rush of air through the fan and duct rather than strictly being mechanical fan noise. It isn't all that bad, especially considering the temperature improvements it produces. So far, well worth the investment but only time will tell. The PC runs 24/7/365 and so will this fan. It's running at full speed now, for the summer months, but I anticipate using the speed control to slow it to half speed or lower during the cooler months. There is a hum from the fan motor at the lowest speed, but it is not all that loud. The fan is mounted underneath the work desk, on the rear panel of the desk, so any hum or mechanical noise is transmitted by the desk. Even at the lowest speed the noise generated is acceptable, but still noticeable.Update 11-12-2021This fan has been running continuously since the day it arrived and is still running fine, doing it's job, with no complaints. You can't go wrong with this one if you want good air flow and dependability.

I ordered this fan to create constant air flow thru a small bathroom so towels dry during the damp months. Bit the bullet on the higher cost after trying a cheap but very noisy in-duct 4" fan that moved a pitiful amount of air. This unit is a LOT quieter and moves maybe ten times more air. (Order the Active Air Speed controller to go with it.) The fan cord has a plug for a wall outlet and there are metal brackets to mount the fan. The fan is heavy and well made so you need something decent to mount it to. You can get a very significant noise reduction by cutting out a foot of metal duct, mounting this fan to a structure that the duct is NOT mounted to, and connecting this fan to the metal ductwork with flexible plastic dryer hose stretched tight so it does not restrict air flow. This keeps any vibration from sounding all thru your ductwork. Use the speed control to adjust air movement, and air movement noise to the desired level. This moves more air thru a 4" duct than the furnace does when it kicks on. Very pleased.

The only problem I have is that I bought the 6inch fan before I purchased this one. So my expectations were higher when I got this ,and installed it. The fans works good, it moves a heck of a lot of air, it's compact, and really easy to install and move around if needed. But when you compare it to their 6inch model, It is almost twice as LOUD as THE 6 INCH ONE!!!!! But don't let that differ you from buying it, and trying it out for your situation. Because the fan works great, and is a great fan for the price, flat out. But when compared to it's bigger 6 inch brother ,it's a lot louder. After I got it, I wanted to try to contact the company and return it and get another 6inch fan like the first one I got. I figured that would be a big process and very difficult, so I kept the fan, and will be buying a USA made 6 inch fan in the next year or so . I am happy with the purchase. Thanks

I've installed this to help bring fresh outside air into our apartment so I don't have to leave my window open and let in all the noise and dirt from the city center in which we live. Coupled to the 4" iPower GLFILT4M Air Carbon Filter I also bought on Amazon, the air coming in is as clean as could be.As for the fan's noise level, we find it very tolerable and it really doesn't bother us in the least. Using a dB meter, I recorded the following noise levels at 5 feet from the exhaust side of the fan: low speed - 52 dB, medium speed - 60 dB, high speed - 64 dB

This fan is great I'm using it for a bathroom exhaust fan. moves so much more air than the cheap one I had in there's there's no steam anymore when I take a shower and when my buddies take nasty you know what 💩 It goes away in minutes it kinda loud for the purpose but it gets the job done really well

Recieved fan today. The air outtake side of the fan had a pretty big dent in it! Fan seems to be working fine. Hopefully it will be ok

As in the description the product is very quiet and super quality

Great Fan.