New construction - Energy consumption of the heat pump / electric auxiliary heater

Well - I don't know anything about heating systems, so I can't provide any help regarding the settings. From an outside perspective, the situation hasn't changed at all, so most of the recommendations here won't change either. If the heating installer obstructs things, unfortunately there are only two options left: have someone else do it at your own expense, or pursue the complaint about the defects to the very end...

This reduces energy consumption, although it still remains around 180 kW per week, which is more than expected.

That sounds like something still isn't quite right. You should definitely adjust the heating curve, which is something you have to do yourself, because only you can tell if it's too cold or too warm. The heating technician should roughly set it correctly (which has already failed) and then you have to take over and lower the settings until the heat pump just barely keeps the house warm. Check the manual for heating curve, base point and slope. In our Tecalor it clearly states "If it is too cold during the transitional period, do this.." You make this adjustment every few days, always observing the effects of the changes. Your heat pump currently has an annual performance factor of about 3.0, which isn't great, but depending on the heating load, no more than 4000 kWh per year should be used. Also, have a look at the hot water temperature; heat pumps don’t like it efficiency-wise when it goes up to around 50 degrees, for example we manage perfectly well with 43 degrees.

Take a look at the target parameters; that's typically where the problem lies. What supply temperatures do you have for the underfloor heating and the hot water? What target temperature do you have in the living areas? Furthermore, you can set from which point the heating element is allowed to turn on at all. This can logically come with a loss of comfort from a certain outside temperature, but every system can only be optimized for certain parameters.

Oh-oh: I just saw that you are using the very old model from Buderus. That could, of course, already be part of the problem. Why didn’t you get the significantly newer and for several years available "WPL AR"?

I was told that the bivalence point is not mandatory and it is a matter of comfort.

Disconnect the house connection box, guys. I would only let them into the house again for possible correction of proven serious defects and under professional supervision.

After further inquiries, I was told in writing that I should set the bivalence point myself if I know the technical stuff so well.
Is that a statement I am supposed to accept? This is not possible from the "user" level.

Neither this company nor a lawyer will set your heating properly.

You now have it in writing that you are supposed to make the settings yourself. Struggle through it yourself or pay someone knowledgeable who can do the basic settings and explain everything to you, including special menus. My first point of contact would be the manufacturer. If necessary, get several contacts right away.

From the "user" level, I was able to prescribe a fixed program to the electric heater, namely that it should switch on from 00:00 to 23:45 when the outside temperature is below -7°C (recommendation for my location). This reduces energy consumption, although it still remains around 180 kW per week, which is more than expected.

Is the heating rod still running significantly? Start regularly writing down all consumption, meter readings, and changes to the settings. Ideally daily at the same time. But only change what you truly understand and never several things at once.

A heat pump is not a gas heating system. To operate it efficiently, you have to set it yourself suitably; no service technician does or can do this: all room thermostats permanently fully open, hydraulic balancing, lower flow temperature via heating curve as much as possible, choose temperature and times for domestic hot water appropriately. It is not unlikely that you will encounter other problems such as poorly sized heating surfaces or counterproductive hydraulics.

It is best to search on Google; you are surely not the first with this heat pump. As a small goal: the consumption should ultimately be below 3000 kWh electricity per year.

So as a small goal: the consumption should be below 3000 kWh electricity/year in the end

In a standard energy-saving ordinance house with a heat pump whose annual performance factor is 3, that is already ambitious. With KFW 55 and an annual performance factor of 4, we barely get below that, but we also like it warmer. Maybe request the documents regarding the flow rates of the heating circuits; for us, the amount was not correct for 1/4 of the heating circuits. That can be adjusted quickly and easily by yourself. But these are actually all just peanuts. In any case, the auxiliary heater must be monitored; it should not consume electricity above -7°C. If it is still running, you basically have a kettle instead of a heat pump. So 1 kW of electricity produces 1 kW of heat instead of getting 3 from 1. And even if it is only activated from -7°C, it doesn’t necessarily have to run, only if everything else isn’t enough. For us, it is set to -10°C, and even on a night with -12°C, it did not turn on. This is by far the biggest lever for electricity consumption at first.

Yes, you're right, I thought it was a current modulating heat pump from Buderus. Let's say 3500kWh