VIVOSUN Z4 4 Inch Inline Duct Fan, 203 CFM Ventilation Fan with Variable Speed Controller for Grow Tent, Indoor Garden Ventilation, Black

These fans are like new just dusty. You can easily take these apart and clean them if your handy enough. It'll help prevent gunk buildup, heat, balance issues etc by keeping components inside clean! Think about it guys these fans are spinning thousands of revolutions per/day in usually pretty intense situations like high heat & humidity! These are good for the value but the efficiency is not that great. I personally did switch to AC Infinity products but only because the pricing was similar and the specs were just better with less power consumption. I use the 6" inline fan with the VIVOSUN inline carbon filter in my bedroom still to this day on low to control my smells when I'm lighting up if you will. It works great still... 2 years later... Sooo not bad but the 6" fan uses 125 watts on high and the 4" fan uses like 80 watts on high. Not very good when you compare them to AC Infinity where their same fans for similar pricing and with programming have double the efficiency using 1/3 the electricity!

It works really good, I'm using it to vent basement workshop fumes and some airborne dust out a dryer vent through the outside wall. It really pushes air. I will say however that 'low' on the variable speed isn't that low. I measured 50 watts running, lowest on high speed. On low speed 57 watts or so. I have it pulling through a 16x20x1 furnace filter in a box enclosure on a 4" dust collector hose. It's not silent, but not what you would call loud either. I wish it could be turned down more i suppose.

This 203cfm metal housing fan isn’t all that quiet but it is definitely more sturdy and less vibration then the plastic housing 190cfm vivosun inline fan. Overall I am pleased with it. The meta housing 203cfm fan weighs more than the plastic 190cfm and will pull down the top horizontal support bar of any indoor grow tent.

I’m new to this fan company. It looks like the fan is centered and balanced. The bearing seems to be a sealed ball bearing. In general sealed ball do not require any serving at all. Products like fans should be designed with sealed ball bearings require no service. But like any mechanical product failures do occur sometimes. even a $60,000 turbo molecular pumps uses ceramic ball bearings and I’ve had failures with those as well. The good thing about purchasing a VIVOSUN product is that they will send you a replacement the next day. VIVOSUN did not require me to send the 4” inline fan back to the factory. So I can tell you with a high confidence that VIVOSUN stands behind what they sell. And their products are well made and the customer service at VIVOSUN is great. I only sent a 10 second video with sound a replacement was sent the next day. I will continue to purchase VIVOSUN products in the future. I can tell you that the complete housing is made of steel. The motor frame is also made of steel and assembled with metal screws. So one is not likely to have a problem with a VIVOSUN inline fan unless it falls from 20’ onto a hard surface.

Changed my review and rating. This looks really well made and is sturdy. I purchased this in 2017 but did not use it right away. By the time i did use it on a second grow it vibrated so bad it was shaking the house and was very loud. I had used the mounting bracket that came with it and lag bolted it to the rafter to make sure it was secure. Either the bearing is bad or its just so far out of balance that is causing a severe vibration. I took it apart to see if it could be repaired and the weights for balancing on the fan are glued in place and none are missing. I am disappointed to say the least. I did my research and at the time of purchase it had a great rating. It still looks new and has about 100 hours of use. Not worth the money in my opinion for such a short life span .

i bought this and an apollo 4 inch carbon filter. i set one on to of the other to filter rooms in my house. it's cheaper than a home filter and actually filters the air. yea it's loud, but it's a wind loud, not a ratcheting loud. you can sleep with wind loud in the same room. it's not an issue. if you run it 24/7, you may want some distance

When I read the other reviews, I was expecting this fan to be much quieter. It would be difficult to have a conversation next to the unit without raising your voice. I'd say it's about as loud as a handheld vacuum. The controls on my unit were wired backwards. This doesn't affect the operation, but it does raise concerns about quality control. The fan moves a TON of air. It could be used as a leaf blower. The construction is very sturdy and neat. Very little vibration, even at full speed. Overall, if you really need to move a lot of air or push it through a lot of duct work, this fan is up to the task, just temper your expectations about the noise.

I bought this for a small grow tent and it's just too much for it. The fan works well and is quiet, but even on the lowest setting, it moves too much air for me. My tent is setup in a cool, dry basement so I need to be able to raise the temps and humidity a bit. With this fan, a humidifier is useless because it circulates the air too often. Even with a a prefilter, lots of bends in the ducting, and operating on the lowest setting, this thing is a beast. It would be perfect for a 2'x4'x5' grow tent if you're running HID in a warm climate, but if you need to maintain a grow room that has a different climate than the intake air provides, find something smaller. I switched to the Terabloom 4" Silent Inline Duct Booster Fan, 47 CFM, and it's perfect for my setup.

I just wanted to let everyone know i bought this unit back in 2018, I am still using it right now. I have not continually used since then but i have used it for approximately 6 or 7 grows through flower for marijuana i have always had it hooked to a carbon filter. I am on my second carbon filter with this unit attached I have it on a timer and i have had it set at all the different speeds this way with no problems. The unit works great and does the job for me moves good air and aids the filter to remove the smell from the very stinky flowers of my marijuana. So 6 or 7 runs now of approximately 2 months give or take a week at 12 hours a day it has been running. Right now im half way through another grow and still doing its job with no issues no extra noise. I have only had good experience with this unit and i would recommend to anyone needing a good 4 inch round duct fan to move air for what ever reason u need. Just hook up a dryer hose and move the air. Very easy to use. Im about to buy another one as i just had another model give out i know this one performs. I will stick with this model.

I got this fan for my 4'x4' grow tent (also a Vivosun purchase) and it is just amazing, perfect for my use. Then only a few months later it started knocking quite loudly, upon emailing Vivosun directly they issued me a full refund immediately so I could purchase another as it was the quickest way for me to get it. I will now buy all my items needed from Vivosun as you can't go wrong with a company that provides this level of service.

This is the second one I purchased. The first lasted 1 year before the bearings started to squeal (more like an occasional chirp). I disassembled the first one for cleaning and decided to buy another one as a spare. I swapped the old one out with the new one. The new one (one year old) is now making the same chirping noise (bearings). Both fans were run on the lowest fan speed. Debating whether I will buy Vivosun fans again. I know others who have other brands that have lasted 3 to 4 years in the same conditions. Admittedly, the price is right but the quality and longevity is lacking.

The seller ia trusthworty and refunded because of troubles written here. The fan broke after a few months of usage. At first, I found it kind of loud compared to the exact same one my friend has. Then, a loud rattling sound started and since I was in late bloom, I had no other choice then to open and see what was going on... I thaught it might be a the cage that had been displaced but no, the bearing is the problem. I love vivosun products but for this one, I just can't put a good review. I just ordered a ac infinity 4" fan. I guess I was unlucky with this one...

This is the 3rd 4" fan I have had. Vivosun sells a 4" plastic and a 4" steel with no speed control or wrap. Spend the extra and buy this fan, it's not much more but it is significantly better. It's exhausting a 4x5 tent through a carbon filter, and on the lowest setting it still creates a good amount of negative pressure. This unit is by far the most quiet. It's still about 60db, well above the advertised rating of 41db, but is a significant improvement over the 71db of the next cheapest model. The cheapest, plastic one, was even more noisy, but I don't have a noise measurement.