Heating choice, what makes sense

How high do you live in the Hotzenwald? Wiki says it's a foggy region with a lot of precipitation and low temperatures... I would avoid p!V and LLWP. Depending on the subsurface, deep drilling (rock) or collectors (if the ground freezes too much for you) Maybe you would be a case where pellets would really be a good choice... ask around the neighborhood (even better, the local plumber) what alternatives there are and what the experiences are.

I take back what I said about the p!v yield... I just checked out Solar server out of curiosity – in Görwihl, a relatively high yield is even calculated...

herrischried is at 880m, collectors are part of the standard equipment there :-). According to the grid, 5kwp should be enough to supply yourself and the heating. That’s why I’m also thinking about self-sufficient power supply. However, the house builder only offers 2.5kwp in the program, and I was concerned whether that would be enough if I heated the cabin electrically with the fan heater.

It shows 400 kWh for the entire January... so 12 kWh per day.. but at design temperature you actually need 5kW times 24 h - so 100 kWh - or do I have a knot in my head?

Do you have - the heating doesn't blare through and heating kW != electricity kW ;)

With an air-water heat pump at -5° already... ;) but yes, you're right. similarly, of course, right. Still, I doubt that 5 kWp is even remotely enough for autonomy.