VIVOSUN Inline Booster Duct Fan 4” 106 CFM with Speed Controller, HVAC Exhaust Ventilation Fan with Low Noise for Basements, Bathrooms, Kitchens, Attics, Grow Tents

This product works perfect !!I started a return thinking it was broke but it was me who didn’t connected right !so I keep it !!good product !

Exact what i need

Ive bought several of these, they work well and move air but some of the controls die after a few days of continuous use. If hardwiring the fans work great

Very low flow but what do you want from a duct booster?

The media could not be loaded. The first fan ordered did not work as it should - when turning the controller knob, there is a humming noise like a voltage transformer and the blades hardly move.Then suddenly in some position the fan turns on at full power and makes quite a lot of noise, about 28 decibels - it's nothing.Turning the regulator knob to maximum turns the fan off.I thought I had gotten a defective fan and decided to replace it with another one of the same kind, so to speak, to give the company a chance.However, the second one has exactly the same problem.Too bad, the window insert for the 4” vent from this company is quality, no complaints.

Overall it does its intended purpose. But I feel like it doesnt move as much air as I would have thought. Also the adjuster knob barely adjusts. The difference between barely on and full blast is pretty negligible.

Really quite, operates perfectly and does the job. Also its light weight, so it mounted up easily.

I have an 800 cfm squirrel cage style blower in my brewery above a pilot system to evacuate heat and steam. The motor can't be exposed to the moisture, so I ducted it through a 4" diameter down-pipe ending a foot above the floor to pull cooler air into the motor.That down pipe proved to be too restrictive to provide enough air to keep the motor from thermal-tripping, so I added this small blower to the down-pipe, and it has made all the difference needed. Where I had been experiencing a couple of motor shutdowns due to overheating on most brewing days, I haven't had any since installing this blower.All that related, this little fan moves just enough air to suffice my needs - it isn't going to impress anyone with the volume it moves. But for an application that doesn't need a lot of air movement, this could work.Cheers!