Ventilation system in the warm summer

you can be. We haven’t missed air conditioning in 5 years. Only during "tropical" nights can you not get the heat out.

For the very precise readers: Heat pump with bivalent control.

No, it simply has nothing to do with bivalence, not even with bivalent control if the heat pump can cool. Bivalence and heat generators always involve the operation of two heat generators and not the fact that it can also cool.

And then you walk around the house in summer wearing felt slippers because the floor is 18°C? I can hardly imagine that being comfortable. We have 24°C in the kitchen right now and it's anything but unpleasant. In our old rental place, which we are currently clearing out, it was 28°C yesterday in the bedroom because the sun was shining directly on it... that is uncomfortable, yes. But 24°C? It's summer after all, let's enjoy the warm days, in autumn everyone will complain again because it's cool and wet.

It is extremely pleasant, never again without. Just as you should keep your brain switched on when regulating the heating, you should do the same with the cooling regulation – that is, not simply set the whole house to an 18° target temperature in summer. Thanks to the condensation control (which regulates the cooling before condensation would occur) and the outside temperature dependency, it works wonderfully; in summer, I only go to the office in the mornings because I can only work at home at sensible temperatures. Currently, I am working on minimizing the time delay caused by the underfloor heating by increasing the cooling early in the morning and decreasing it in the afternoon, depending on the battery charge level, photovoltaic yield forecast, and weather forecast.

And then you walk around the house in summer wearing felt slippers because the floor is 18°C?
I can hardly imagine that being pleasant.

Honestly? I find it super comfortable! You come in from outside and the floor is nicely cool. There's nothing better for me.

Parquet naturally feels (or is even?) warmer than tiles. But even the tiles in the hallway I find really good when the cooling is running.

During the day, I cool from 22°C based on the average outdoor temperature over the day. It’s already pretty warm outside during the day then. I’m happy about the cool floor. When it gets colder again, the cooling switches off and I don’t have cold feet.

Disclaimer: I hate hot feet, better too cold!

Honestly? I find it super pleasant! You come in from outside and the floor is nice and cool. There's nothing better for me.
(...)
Disclaimer: I hate hot feet, better too cold!

My wife HATES cold feet and still LOVES our cooling.

In our house, we have all kinds of floor coverings. You feel the cooling the most on tiles, for example when you come in barefoot from the pool with wet feet. You know what most people do when they come in and the floor is cool? They stand there with a blissful face and say, "oh, this is pleasant, I have to stand here for a moment." With carpet, whether fixed or laid, you only notice it because the warmth is gone. At the moment, I have the cooling on quite often in the attic because the heat gets trapped there – despite central ventilation.