Bathroom fan - What power is needed?

I have already read that a bathroom fan should exchange the room air 6-8 times per hour. I want to be on the safe side and calculated for my bathroom 3.5x3x2.5 = 26.25m³ = 25m³ x 8 = 200m³ fan capacity Now... A fan with that capacity is apparently not very common. At least most of them are often smaller in size. In addition, showering, with a bit added, takes about 10-20 minutes and bathing 30 minutes.. Do I really need a 200m³ fan, probably not? The bigger ones I find have 150m³. Isn't that enough? I don't know if I'm making too big a deal out of it... I have an exposed roof truss that should remain untreated and I don’t want to take any risks there. But maybe that's also an advantage because the wood can absorb some moisture and slowly release it again? How well do these humidity sensors work? I would spontaneously set mine to 60 or 65% to avoid mold and “wet spots” on the wall and the wood. I would rather avoid wiring it to the light. Better an extra switch that starts the after-run time or simply lets the fan run until you turn it off again. Basically, I would fully rely on the sensor, it’s the most convenient after all. What kind of fans do you have in your bathrooms? I'm sure I'm not the only one with 10m² floor area and about 2.5m ceiling height. €: In addition, many fans only have an after-run time of about 20 minutes. That would mean a fan with 150m³ exchanges 50m³ of air in 20 minutes, which is just twice the amount. So far from 6 or even 8 times exchange. So somehow this doesn't add up at all... if the fan runs for 20 minutes after use and in this time is supposed to exchange the air 8 times (since in the remaining 40 minutes of the full hour “no” exchange takes place). So then I would need a 750m³ fan... I don’t know offhand, but I think even the exhaust hood above the stove doesn’t have that.

I can't imagine what you read somewhere - that's probably why you can't find any fans

Entire houses have such air exchange rates...

In our 12sqm bathroom, I have an air exchange rate at nominal ventilation of around 40m3 - and that is a calculated value from the planning regarding moisture protection.

I have no idea how much air exchange my fan provides, I would have to check, but the fan itself automatically turns on at a certain humidity level and I also have a manual control (a rotary switch that can be set anywhere from 0-15 minutes and then runs down, like a kitchen timer)

My range hood has 600m3 on the highest setting. Maybe something like that above the toilet would be an alternative.

I find that exciting. I would also combine it with the toilet lid as a switch.

Even Punkt de writes that

[auch die lüftungsexperten schreiben es]

you really read it often.

I stick to it... [Dunstabzugshaube].