So then you just need it above 20% to prevent static build up, good to know.

Yes it runs circles inside the hot room, thus creating pressure against the (asic miner) fans. This is what i meant with my post. To understand "pressure", just put some obstacle near the exhaust fan of one unit, such as your hands, and watch the temps.

In my opinion, there should be only fans in the inner wall (no vents), and the outer wall better have lots of vents (or big enough) so the air can go easily.

And yes I'm only referring to the exhaust part. Intake is probably fine. Funny you didn't just mirror that, a vent is not a cheaper fan, it lets some air go in the opposite direction...

Oh and BTW, this hot room try to make it walk-able, you'll find it very useful for some unrelated things later. Think, giant clothes dryer Just don't abuse it and create unwanted pressure lol.