Underfloor heating in the children's room? Some rooms planned without underfloor heating? Air-to-water heat pump removed?

Nobody wants the temperature of the living area to be the same in the bedroom

The valves in the heating circuit distributor are first roughly manually adjusted based on the heating load calculation and later fine-tuned during on-site testing. After that, the heating in the house is controlled solely by the outdoor temperature sensor. This is sufficient for modern houses. Search for "hydraulic balancing". It has been discussed here in the forum many times over the past few days.

Have the underfloor heating planned based on a room-specific heating load calculation to achieve the lowest possible supply temperature. All circuits around 80 meters, max 100.

Additionally, with LWWP, max 10 cm installation spacing.

That depends on the room and is calculated. We have between 7.5 and 15. The circuit lengths should also be consistent; larger distances can sometimes make sense in rooms with low heat demand.

yes well then I will always run the underfloor heating, but how do I regulate different temperatures? No one wants the temperature of the living area in the bedroom too?

Basically, you can regulate them differently and have different temperatures in the rooms.

Many don't want to believe that here.

Can you make different flow temperature circuits with an LW heat pump?

This is controlled via the valves of the underfloor heating and the room thermostats.

Basically, it is wrong not to heat rooms. That sooner or later causes building problems.

Nevertheless, ancillary rooms are then kept at around 18 degrees, living rooms at about 21 or so. Doors must then be closed.
And yes: spontaneously tinkering might make it uncomfortably cool. For that, possibly use an electric radiator or simply run these infrared heaters temporarily on electricity.

But the handling and setting should still have enough time for you until it comes to that.

The same applies to the bedrooms. I can’t sleep well in the bedroom at temperatures > 18/19°C. How is it supposed to work if I go from the living room, where hopefully it’s a bit warmer than 20°C, upstairs to the bedroom, which isn’t also 21-22°C with the same underfloor heating.

Of course you can also sleep at 20°. I didn’t want to believe that before either, I also belonged to the “the window has to be open even at 5°C, otherwise I suffocate” faction. But everyone can get used to it already, thanks to climate change. Otherwise, you probably have to emigrate to Iceland or something. In the bedroom, of course, you can have it a bit cooler with underfloor heating than in the living room, as long as the door stays closed. Still, it’s simply warm everywhere in summer. Last summer we often had 24° despite everything being closed during the day, ventilation off, and everything open at night as soon as it got cooler. Unfortunately, there were nights when it was hardly cooler outside than inside – and you can sleep in that, too.

where we are back to the topic. There are people who can sleep with light, there are those who like it pitch dark. There are people who need 15°C to sleep. There are those - like you - who can sleep well even at 20°C. But here I would also like to bring science/medicine on board, which to my knowledge says that below 20°C is definitely more recommendable in the bedroom. But to each their own

Because you wrote something about ventilation, you have a ventilation system, right? Can’t you also cool with it in summer when it gets warmer than XX °C in room XY? Of course, that depends on the heating, with an air-water heat pump you then cool with electricity. But with a trench collector brine heat pump it is easier to cool in summer (in the ground clearly below the 30°C air temperature during the day), isn’t it?

Because the trench collector on a plot of about 1000 sqm in DIY and the generous subsidy of at least 4k also seems to become interesting.