Help with should I go 6 or 8" fan.

Budjam

Member
Hello
Trying to decide on what fan size to go with here.

I have a 2x4x6 (60cmx120cmx180xm) tent, At the moment I have a standard 5" rvk ac fan, the fan is situated in loft so ducting runs from CF in tent to fan in loft about 1.5m away.
I have it on a decent no whine/hum controller and have it throttled back to about 40% speed, problem is the fan is fairly noisy still and at night you can hear it chugging away in the loft even tho it is suspended and covered to minimise noise.

I want to go with a new stealth EC fan with controller, What do ya'll think would be best, a 6" or a 8" and throttle it back even more? Will also get phonic ducting to go with it.. Don't mind the cost if it means I will have a very quiet setup.

I'm looking at either a Systemair Revolution Silenced Vector EC Fan in 6" or 8" or a TD-SILENT ECOWATT Mixed Flow Fan 6" or 8" with controller, any help with these 2?
Just to say I did try a phresh stealth hyper fan 6" with controller but it seem to make a high pitched hum resonating through the walls.

Thanks all
 

Wattzzup

Well-Known Member
I have a 6 inch in my 4x4 and it sucks the sides in so hard at 50% I wouldn’t want an 8 inch.
 

Renfro

Well-Known Member
The thought was go big and turn right down to minimum ?
I did that with a 10 inch vortex in a 2x4 tent. I run it very low, can't hear it and it sucks the tent in hard lol I had to put two high CFM kits in there.
 

Budjam

Member
Now that is a huge fan :)
I'm leaning towards the 8" Systemair, have it turned down as much as I can (fan is 0 - 100 on the controller)
 

Renfro

Well-Known Member
Now that is a huge fan :)
I'm leaning towards the 8" Systemair, have it turned down as much as I can (fan is 0 - 100 on the controller)
I prefer a VARIAC, some cheap speed controllers will make a fans motor groan at reduced speeds because it chops up the sine wave.
 
Hi

so your saying just go with the 6 inch as fan it will be plenty even when turned down for noise?
Take my advice with a grain of salt, but I'm pretty sure that what you are looking for is the CFM (cubic feet per minute) of the fan. For instance if you have a 200 CFM fan and a grow tent that is 2x4x6 (48 cubic feet) it will exhaust the volume of that tent in 0.24 minutes or about 15 seconds (48CF/200CFM).

With that being said I'm more or less certain that yes, the larger the diameter of the exhaust housing duct = larger volume of air an exhaust fan will move. Just makes no sense for a manufacturer to make a duct bigger but not put a stronger motor in the fan assembly.
 
Also keep in mind that is 200 CFM at atmospheric pressure. If your tent has nowhere to draw that air in from you essentially have a shitty vacuum chamber.
 

DCcan

Well-Known Member
You can use 8inch ducting to run quieter, reduce air turbulence and noise.
Just use an adapter to a 6inch fan for a 2x4 tent. That should run fairly silent and still pull plenty of air.
The same applies to a filter, use an 8inch/large 6 inch filter to run quieter, the air will have be scrubbed better and reduce another noise generating area.
 
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