I just purchased this fan from Amazon and will give you the lowdown on this duct fan.
This 6 inch Hydrofarm inline fan is rated at 400 CFM(cubic feet per minute).
I have seen some sellers rate it at around 440 cfm and this may be true but the box says 400 so that is what I would expect to get out of it.
The packaging is quite simple with the fan wrapped in bubble wrap and mounting brackets underneath the fan on the bottom of the box.
I have to say this is a very solid and sturdy little fan. The housing is powder coated steel and it feels like if you drop this fan it will do more damage to the floor than to itself.
It also has a nice heavy duty cord and comes completely assembled so once you mount it the fan is ready to go. So I plugged it in and I will tell you this little fan really can move some air. The manufacturer promises quiet operation but we all have different ideas of what quiet is.
How Loud Is The Active Air 6 inch Inline Fan?
I found a video that compares Active Air, Vortex and Ecoplus 6 inch inline fans. The Active Air in line fan was trhe quietest of these 3 popular brands. However this fan is not quiet by any means as you will see in the video.
Most of the fan noise is actually caused by moving air so all fans will be quieter once the duct work is in place. You will also notice in the video that these fans are mounted on a wood table. Hanging your inline fan by bungee cords will help eliminate vibrations and make your fan quieter.
Other options to quiet an inline fan are placing it in a wooden box with soundproof foam and using a duct muffler. Here is a short thread on soundproofing a fan.
Another option is to run your fan with a fan speed controller and this will definitely make it quieter. It is fairly common practice to buy a fan larger than you need for your grow room and then run it at lower speed.
This fan should have enough power to cool 2 6 inch hoods easily but I bought mine to run a homemade swamp cooler I built. It is upside down in this picture but you can see it fits quite nicely on a bucket lid.
Unfortunately this fan was just too loud for my apartment and the way I was using it didn’t really allow me to do any sound proofing. It is a great little fan but I will probably sell it and get something quieter and a whole lot more expensive.
Should You Buy The Active Air 6 inch Inline Fan?
If you are looking for an inexpensive little powerhouse this is a great fan providing you are not running a stealth grow. If you are willing to spend some time and money quieting it down you may even be able to make it work for that.
I was willing to take a chance on Hydrofarm Active Air 6 Inch Inline Fan because of the price and I think this fan is a great value. But I am running my cooler with a Soler and Palau TD 100x which puts out much less air but is very nearly silent.
If stealth is your goal I would recommend Soler and Palau fans wholeheartedly. I have 2 of them and they are very quiet and have been running them for years with no trouble.
This 6 inch fan is extremely quiet and puts out H:333 cfm, L: 239 cfm. aLL S&P fans can be wired to run on high or low speed.
This is an 8 inch Soler&Pilau in line fan that puts out H: 530 cfm, L: 409 cfm. If you want a 400 cfm fan this is a great choice and you wont need a speed controller for it. You can buy 8 to 6 inch reducers for under $10 each if you run a 6 inch system