Ventilation system in summer?

Hello everyone, I hear different opinions about this. How is it with the ventilation system in summer, turn it off or leave it on? I have noticed in the last few days when it was warm outside that the heat also came in through the ventilation system. The supply air was already at 24 degrees with outside temperatures of about 28 degrees, no wonder the house gets warm then. How do you do it?

Well, if you turn them off, you have to ventilate by hand, and whether that then reduces the effect of heating up, I would doubt... and once the warmth is in, it stays... ergo our system keeps running...

Phew, good question. Turning it off is not an option here because then the air in the house immediately becomes heavier. At night, however, the windows in the attic are open. I am also open to ideas.

Well, I can turn it off during the day and turn it back on in the evening when the temperatures are milder.
Don’t you have the effect that your house warms up because of the system?

In the evening/night/morning it gets cooler, during this time the controlled residential ventilation makes a lot of sense again

We experienced that in the last two summers as well and therefore want to try it differently this year.

We reprogrammed the system last weekend.
Completely off during the day (we are not at home anyway, so stale air does not bother us) and instead on level 2 at night when it is cooler outside.

The air does get worse when the system is off, but I have the feeling that it still achieved the desired effect. The house heated up significantly less on the last warm days than last summer. We will keep it that way for now, but may switch back to normal operation during longer periods of bad weather.

P.S. How old is your house? Is it already dry?
Our house (2 years old) is already dry (humidity on normal days mostly around 30-40%, so actually already too dry), so there should be no problems if the system is off during the day.