Electroinstallation too expensive - oversized or too expensive?

Therefore the quick yes in "..." I primarily wanted to say that you can quite easily change the temperature in a room. Of course, you have to experiment a bit with the draft diverters, as you correctly call them. With ours, you have about 23.5 - 24 degrees in a "standard setting" and then I just remembered 2-3 other points that I consider useful, for example, for the hallway, (unused) guest room. Of course, you have to try a bit with a thermometer and a few hours or 1 day "settling process"... But about the hydraulic balancing, you always read about it. Can you do it yourself? My assumption was always that the valves open when the thermostat says it’s too cold and they close when the desired temperature is reached again?

No, you can't do it yourself, because that is a relatively complicated calculation... if, of course, someone calculates everything for you and then only tells you the valve rotation speed, then yes, you can turn the valves yourself.

Simple thermostats are just guessing devices... just unscrew one and then you'll know what I mean...

My assumption was always that the valves open when the thermostat says it is too cold and close when the desired temperature is reached again?

That is exactly the assumption of the average consumer... it is not fundamentally wrong, but also not right...

This approach is just like always driving at full throttle and only controlling the speed with the brake... nobody does that, right?

You only give as much gas as necessary...

And ERR are nothing more than "emergency brakes" — when the room is really already too warm, it gets choked off... when it gets too cold again, heat is added, and so on, it swings back and forth... but that is a long story...

Without ERR and with a well-balanced system, the comfort temperature is maintained permanently and there is hardly any fluctuation...

That you usually have the same temperature goes without saying, but I like to turn the heater up a bit when, for example, I have a cold or 2 degrees lower when I'm away for a few days. Then I don’t want to have to adjust the heater itself all the time, but just slightly adjust 3-4 thermostats...

Yes, to each their own... one person simply wants to save energy and costs, the other wants to tweak the RTRs... what you ultimately want is something you have to decide for yourself...

That you usually have the same temperature is unquestioned, however, I like to turn the heating up a bit when, for example, I have a cold or 2 degrees lower when I’m away for a few days. Then I don’t want to have to adjust the heating itself all the time, but only adjust 3-4 thermostats a little...

In case of that, I also have two options without RT:

[*]Wood stove on
[*]Increase the target room temperature on the heat pump

I don’t find 110 much at all. I think I have a rather small house, and there are at least 10 sockets per room (children’s, guest), and in many significantly more (kitchen alone 8 above the countertop, 4 on the cooking island), living room alone at the multimedia spot over 10 (partly switchable together, some with constant load). 110 get filled up quickly...