Newly built single-family house KfW55 standard - How to heat?

what are you getting so worked up about the hot water for? We have consumed exactly 114kWh of electricity (measured by a separate electricity meter) in the last two months. That’s not even quite 30€ for two months and the photovoltaic system is not taken into account at all yet.

The storage tank is not sized according to the number of people, but according to the size of the solar thermal system.
It needs to be large enough because especially in summer the water heats up very quickly and the system stagnates. This puts a lot of stress on the heat transfer fluid in the system.

Do you have any information on this or where I could read about it?
So far, I haven’t found anything about how the system could be damaged by a smaller water storage tank; I had assumed until now that excess solar-heated water is simply vented like with a pressure relief valve.
Isn’t it rather the other way around, that the size of the solar thermal system is oriented according to the calculated water demand?
Thanks.

Why are you getting so worked up about the hot water? We have used exactly 114 kWh of electricity (measured by a separate electricity meter) in the last two months. That’s not even quite 30€ for two months, and that doesn’t even take the photovoltaic system into account yet.

Wait until winter. I don’t have any significant consumption now either. But our system has been running for 5 years already and was not the latest model back then. Especially if it can’t modulate.

I have already gotten through the winter, as well as a current modulating device.

Then you also have consumption values from the winter, and there it is more than 110kw for 2 months.

Do you have any information on this or where I could read about it?
So far, I haven’t found anything regarding how the system could be damaged by a smaller water storage tank; until now, I assumed that excess solar-heated water is simply vented like with a pressure relief valve.
Isn’t it rather the other way around, that the size of the solar thermal system is based on the calculated water demand?
Thanks.

Google is your friend. Please also do your own research.