But on average? Does the average person have a home server? A desktop PC?

I don't know any non-techy person who isn't using a laptop exclusively, and then pretty rarely, as most things nowadays happen on the smart phone. AC is non-existent in Germany. So I'm really curious. I have a 24/7 Homeserver and laptop, and am at ~1200kwh a year.

I'd agree normal people don't have those things, but also add that things not mentioned — e.g. TVs, ovens, and fridge/freezers — will add up. At such a low average, even lighting will contribute non-negligibly.

Two questions though: how common are TVs in Germany? And how common is electric hot water for showers/baths? My sample size is pretty small (and mostly limited to Berlin).

I'd say TVs are still the norm, my social circle is 30~50 and o think everyone got one, for streaming mostly. As for the older generation it's also still a thing you just need to have. As for sizes, I think they've also increased over the last decade or two, but at least in the cities if you're limited to a smaller place I think people go for 40 rather than 50 inches. Can't really speak for the younger generations, but I feel they're more comfortable watching stuff on their phones, college students probably also due to financial or space reasons.

Hot water mostly comes from central heating with gas, some homes in my city have district heating. At least up until now, electric heating, be it for water or the whole apartment was way to expensive so that you'd only consider that if you really have no other choice, for example, an old building from 100+ years ago with retrofitted central heating might have an electric water heater for the kitchens as they only did the bathrooms.