I recommend you listen to those things – a PC fan that is in front of you is already louder. I found it audible at level 2 if you concentrate a bit. Audible at levels 3 and 4.
I am currently sitting in the living room watching GI Joe.
Meanwhile, I am typing here on the laptop.
I don't hear the fan at level 2 at all. However, I do hear the laptop’s fan that starts up from time to time.
OK – the action and music of the movie, by the way, overpower everything else.
You can ventilate through closed windows if you have a ventilation system or at least an exhaust system.
Regarding ventilation through the windows:
By extracting the used or humid air, a suction is created, for example, over the roller shutter box to supply fresh air again. Perhaps explained in layman’s terms, but as far as I know, it doesn't work at all without electronics.
That means, in reverse: you will have to tolerate some noise.
The difference to a system with heat recovery is that with window rebate ventilation, cold outside air is sucked in.
In addition, to achieve the same ventilation effect as with a ventilation system with heat recovery, the exhaust fans in the wet rooms (bathrooms, kitchen, etc.) would have to run continuously. So then cool air from outside would also be sucked in continuously.
If the low noise level of ventilation with heat recovery bothers you, in my opinion there are only two options: a central ventilation system (although I don’t know to what extent you might hear something – but there are plenty of people here who can report about that) or regular shock ventilation through windows.
(a small disclaimer here – as a layman, I also don’t know the entire market for ventilation)