VIVOSUN D4 4 Inch 195 CFM Inline Duct Ventilation Fan HVAC Vent Blower for Hydroponics Grow Tent

I use this in combination with a VivoSun 4 inch carbon filter to eliminate the smells from my plant tent. the air flow is really good although not adjustable. installation is super easy and the build quality is amazing. it both cleans the air and cools the area at the same time. the only thing i wish is it was a little bit quieter. unless this is in a closet or behind closed doors the sound might bug you. but it doesn't claim to be silent so i’m still giving it 5 stars. I have bought another one since and love them both

The first one I received only worked about 10 minutes. But you're going to find a faulty product once in awhile. But I will say they were super quick and then response from customer service and sent me a replacement immediately. It moves a lot of air

definitely much louder than the advertised 30dB. Not having a fan speed control or power switch is a nuisance, especially in conjunction with it being so loud. But at $27 it was a reasonable compromise at the time.

Used this to help vent car exhaust from my garage for troubleshooting purposes. Coupled with some flexible dryer-type hose, this works great to keep me alive if I need to run the car in the garage.

high quality and low noise level wit the best air flow

It's cheap, it has exceptional airflow, but there is no speed control and it's very loud (I measured 55db from 3 feet away). Since I'm using it to ventilate a 3D printer in a home office, this is way too loud. If noise isn't a concern for you, this is an excellent bargain option, but if you are placing it somewhere like a home office where you will be spending time, I'd recommend spending a little more on a more quiet (and speed-controlled) option.

The media could not be loaded. No problem with seller. I bought a both the Viviosun D4 and M4 fans and compared them side by side. The single speed fan was 6 db quieter. The variable speed fan sounds like its out of balance. I am using the D4 fan as a Radon pump. It pulled the radon level down from 11.2 pCi/L to 1.5 pCi/l. No point spending $350 for an official radon pump when this will do the same thing. A little air leaks out between the two halves of the plastic shell. I had to put RTV silicone on the crack to seal it up because some sub-slab radon air was leaking out into the basement. Also (if you do this) you need 3 inch duct collection cuffs to connect it to PVC pipe. The 3 inch rubber cuffs you get from the "home center" store are too small to fit the fan.

Works alright, very cheaply made.