Quote from: huntingthesnark on April 26, 2018, 02:58:52 PM

I'll leave the maths to the clever people, but having done several similar tests, I can tell you that 6in ducting is not wide enough. 8in can be but it's a struggle - you'll need an epic inline fan that'll eat serious wattage (and cost hundreds for a specialised industrial fan unit).

You basically want the biggest extractor fan diameter you can fit - bigger fan, lower RPM = quieter, cheaper to run.

How does ducting diameter matter? I thought only fan capacity matters, cfm. You can have a fan pull, say, 1000 cfm through a 8" duct and you can have another more powerful fan pull 1000 cfm through a 6" duct.

On a side note, I see nobody mentions which area of the box or tent get ventilated more and which less based on fan placement... in my case I measured temperature in various corners of the tent to find differences of up to 8C even, so some spots in the tent did not get ventilated enough despite having 2 x 500 cfm fans on the exhaust.