4" Inch 190 CFM Inline Duct Fan with Built in Variable Speed Controller for Ventilation

Very happy with it. Quieter than I thought it would be and more powerful. Have a 12 x 13 utility room and removes air and odors very quickly. Have 25 foot horizontal 4" flex duct run to outside and the air coming out of vent is nice and strong. I usually run it at full on and it does run with a hum at lower speeds as with most all variable ones but noise is not a concern with my operation. Do not really know if the CFM is really 190 or if the wattage usage is really that low at 35 or so, but all in all I did my research and had lots of choices for what I wanted and so far glad with purchase and would recommend.

A little pricey but works well. Nice quality and quiet. No vibration. Strong air flow. The only con would be the price. I think it could be a bit cheaper. 4-8 inch ends sold separately would be a nice option.

A little louder than I anticipated, but works great after nearly 1000 hours of use.

A great fan for the price. I've used other duct fans in the past and they are cumbersome and loud. This is just the right size and virtually silent. I highly recommend this fan for those who don't need the fastest most expensive fans. As a 20 year member of Amazon I rely on independent reviews when shopping. Therefore, I will always try to be as honest and impartial as I can and will try to provide helpful insight into the product. I am reviewing this product as it relates to how it works for me in my intended use. Your needs and experiences may of course be different. I tend to review products that I really like, or that let me down in some manner. If you found this review helpful, then please click the "HELPFUL" link below! Thank you, and HAPPY SHOPPING!

Upon unboxing the item, I was pleasantly surprised to see that the fan was constructed in durable materials. While the 4" version is anemically weak in all but it's max setting, the 6" blows a good amount of air. Don't fool yourself into believing the 4" model will flow 190CFM. I doubt it would flow that in free air, but it certainly won't hold up to static pressure of 90 degree elbows or carbon filters like a centrifugal fan design will. Furthermore, I do not believe it will flow enough through a carbon filter to b of use to many people. The main problem with this design is its cheap motor and fan control. This thing really hums which makes me question whether it is a variable speed motor, or if it is just a AC motor with a rheostat. Several articles state that attaching a rheostat (dimmer) to a fan is a serious fire hazard, and I did see where another customer showed one that caught on fire. The manufacturer states that the fan registers less than or equal to 30 decibels (dB). I measured it at 1 meter at 56dB on low and 65dB on high. The manufacturer must have been measuring from an adjacent room or some other deceptive manner. For exhausting bathrooms silently look at the Panasonic Whisper line and never look back. If you need a quiet, small inline, everyone is impressed by Soler & Palau. This seems like a decent fan, but if you are going to put up with the noise, why not get a better constructed metal centrifugal fan? This fan idea has promise, but they need to get a properly designed 3-speed motor that has specific windings to each speed. This should eliminate the hum and make a great product. While I gave the 6" model 3 stars for at least moving air forcefully, I gave the 4" 2 stars for being very weak. (I've posted details of the 6" model on the relevant page)

I ordered the 4 inch inline fan and it's not that bad. The product description says 190 cfm but the owner's manual you get with it says 117 cfm. It might do the 117 cfm not the 190 cfm for sure. It works good for a small tent tho. The built-in speed controller is nice and works great. The power cord is only about 4 feet long. It's not loud at all looks and feels to be made very well even though it's made out of plastic. I would buy this inline again. UPDATE. One of 2 i ordered in may just pooped out on me and its August didn't last long. I woke up and smelt burnt plastic. Took it apart the entire inside was pretty much melted melted so bad and burnt a hole right through and you can see daylight. I will not buy Apollo name anymore. BUYER BEWAER

Tha Duct fan is working ok i have inside a small space (approximately 128 to 150 cubic ft) , its not TOO loud but is definitely making noise when its on especially on the highest speed I can hear it from the next room. One thing I noticed is its not as powerful as I would like it to be, It doesn't seem to suck the air out as fast as I expected, still for the price its a decent value.

This product sucks the air out of my Apollo 4'x4'x7' grow tent just fine. It is sitting on a shelf 2ft. above said tent and pulls air out thru a 6" carbon filter inside and then pushed 10' thru to a vent in my ceiling and out an 8" roof vent. It's been on and running quietly 24/7 since the moment it arrived well packaged 2 months ago. Awesome fan to exhaust a small indoor area. The variable speed is a nice feature as during certain phases of growing and/or climate conditions require more or less flow at times. The unit can sit/rest on a shelf or has holes in the base to accommodate wall/ceiling mounting. I have 3 now, one in a grow tent, one in a dry tent and a back up just in case.