Heat pump for KfW55 house 148 sqm

And picture 3
The "solution": the 11 in the middle stands for 11kW

I don’t understand that.

At Daikin there are apparently two heat pump classes:
4-8kW
11-16kW

If the Daikin program calculates a surcharge for hot water on top of the heating output (7.48kW), you automatically end up with the 11kW machine.

So a surcharge-surcharge-surcharge?
Suspenders-belt-garters?

Where does the heating output of 7.48kW come from, that is the number?
We started at a good 5kW standard heating load.

According to BL, we have such a large house.
hm....
Another project in the construction area is 2sqm larger, almost 6kW standard heating load. That resulted in an 8kW system.
Same BT.

So, a surcharge-surcharge-surcharge? Suspenders-belt-garter? Where does the heating capacity of 7.48kW come from, I mean the number? We started with a good 5kW standard heating load. According to the building permit, we have such a large house. hm.... Another project in the development area is 2sqm larger, with just under 6kW standard heating load. That resulted in an 8kW system. Same BT.

Don't let yourself be fooled, we have 250m2 and an 8kW heat pump and even that is too big. A 6kW would have been enough. But to be on the safe side, have an energy consultant do the calculations with the correct room temperatures and pipe distances.

Where does the heating capacity of 7.48kW come from, that is the number?
We started with a good 5kW standard heating load.

No idea how the Daikin program calculates...
For me, with 4 people and your data from the heating load calculation, a proposal for a 7kW unit comes out.
It has a bivalence point at -7.4°C, but the use of the electric heater should not cost more than €50 per year.

Edit: I even calculated with a 4-hour grid operator lockout ;)

The tool that you used to calculate the heating load in #42 is well-known and proven. That works fine. Everything else is, as already mentioned, suspenders on a belt. But if you take safety margin on top of safety margin + poor planning + ERR + DAU + monovalent sizing -> then you end up with such an 11kw monster. As wrote, design it bivalent. You need an appropriate device for 90% of the time. The remaining 10% the electric heater doesn’t really make a big difference. Although even there it’s questionable whether it’s needed. Because usually we don’t have many consecutive days below zero. And solar gains aren’t really taken into account either. It should be clear by now that this is completely nonsense. The question is how to get the cow off the ice (if at all).

Then completely different numbers appear again, suddenly an outside temperature of -8.6°C is being used.

That was a sticking point for us, where I made progress. In the old standard, the values are even higher (-12°/-14°/-16°). However, according to my understanding, that no longer applies, and our contract stated that the heating system is designed according to the standard temperature. So it was also calculated with -14°, but for us the correct value would be -11.3°C. You can simply find the current values via Google (standard outside temperature). The value of -8.6° is therefore probably correct. Maybe you can shake up your builder by telling him that the planning was not done according to the standard and that you definitely want a new plan. For us it was only about the calculated flow temperature and installation spacing, but maybe that is an approach.

You don't have to factor in the 4 hours dead time, do you?