The children's room is too warm in the new building.

Only on the upper floor do I now have the phenomenon that the floor of a room becomes relatively warm.

That shows that the heating curve is too high. Therefore, that was a good hint:

Please urgently deal with the topic of heating curve, hydraulic and thermal balancing.

With the correct setting of the heating, the wheat is separated from the chaff.

Companies that cannot handle this have either neglected to continue their education or are simply "plumbers" without understanding what they are doing.

For me, the floors only start to get slightly warm when there are sub-zero temperatures outside. At the moment, everything is cold. Nevertheless, the set temperatures are reached everywhere.

That's where I want to go too. I have already started reading up and trying to understand the whole systematics. Now I at least know how to calculate the heating load to determine which flow rate I need for the individual rooms. Now the question would be how to set the whole thing correctly.

As far as I have seen, the flow rate changes with us depending on how many rooms are heated at the same time. How do you then set it correctly if the value always varies anyway?

So you do the following first: you check how to set the heating curve on your system. Then you open all valves etc. fully. Wait 24 hours. If it is too warm everywhere, you lower the heating curve. You do this until one room is no longer warm enough. Then we'll see further.

You don't calculate anything here anymore. You balance thermally. There are a ton of instructions for this that only require some understanding and patience.

I just looked at our Vaillant heating system and saw that the heating curve is set to 1.1. Isn't that a bit too high? According to the chart, the water should be heated to 40 degrees at the current outside temperature. However, it is capped at a maximum of 35 degrees. Edit:// I have now seen that the water temperature has been limited to 35 degrees.

40 or 35° is too high. In the worst case, you should need 35° flow temperature when it is really cold. The underfloor heating circuits need flow for this: keep thermostats permanently open. Lower the heating curve until it is no longer too warm, then adjust the circuits. Take your time and don’t change too much at once. Notes help. I cannot contribute anything to the setting on Vaillant.

Example of a heating curve in a new building: 24° flow temperature at 10° outside temperature, 30° flow temperature at -14°.