Controlled residential ventilation and still open windows at night

Strictly speaking, this can hardly work - if everything is really sealed.

And I can't just quickly ventilate a house on three levels in the morning/evening - especially not the basement. It's also not guaranteed that mold will form immediately, but the risk is significantly higher - and often you only see the mold when it's too late. Especially now after the construction phase, I enjoy the comfort of the system - I couldn't ventilate that much anyway.

Explain the statement to me:

Sure, the controlled residential ventilation does not heat the air, but it draws in warm outside air.

- and still: The heat exchanger also works the other way around.

because you wrote "get one" and not "don't get one"

ok, then I think I understand it now:
make sure that it just blows and has no control technology, then you can also easily open windows
higher wear could occur or not

I would possibly explain the wear like this:
a certain electrical voltage is applied to the fans, normally resulting in the airflow set by the heater
if I now open a window or a door, the airflow could cause more or less resistance (depending on whether and how overpressure or underpressure occurs through the window)
either it becomes easier or harder for the fan to turn. so the fan either spins faster (which could lead to higher wear of the bearings etc.) or the fan spins slower (which could cause issues in the drivetrain etc.).

overall, in my opinion, that wouldn’t matter because if the system was set stronger or weaker, you would have the already mentioned "undesired" mode permanently anyway, I think it doesn’t make much difference.

now one might think that the short alternating "like this and like that" could cause problems, but then you really wouldn’t be able to get back inside the front door.
in contrast, airing for several hours would be similar to a constant mode just at a different level of the controlled residential ventilation system.

whether that’s true or not, no idea, I’m not an expert, but that’s how I imagine it.

Well, I see it like you do, that it's just taken a bit too far

Why don't you turn off the controlled residential ventilation completely in summer? During the day, you only bring in warm air with it (even if the controlled residential ventilation can perhaps cool the outside air a bit) and at night a fully opened window upstairs is simply more effective.

I would spontaneously answer that with "fresh air," nothing else. As far as I have read, however, there are also many who do switch off the system.

The sentence referred to your above statement that a controlled residential ventilation system can neither cool nor heat. That is logical, as the controlled residential ventilation system is neither an air conditioner nor a heater. The heat exchanger only tries to transfer as much energy as possible from the exhaust air to the incoming air (or vice versa in summer). However, it will never be 100%. Therefore, with each air exchange, the air inside the house warms up. In addition, every electrical device generates energy. In this respect, the controlled residential ventilation system is also counterproductive in summer (unless it is outside the thermal envelope). Therefore, I wonder why energy (electricity) is used to heat a house when I want it to be cooler.

However, I must make one restriction. As I recently learned here in the forum, there are also people who need complete darkness at night. So anyone who has their roller shutters all the way down obviously cannot ventilate at the same time.

PS: I always speak from my own experience. A bomb could explode next to me and the sun could shine into my face, I would still keep sleeping. My wife is similar and our child inherited it from us.