Because they are power-hungry and everyone knows that.

More generally because the climate in central Europe is not like Arizona, Utah, New Mexico, California but hospitable during the summer season without AC.

AC makes it more comfortable during hot days but it is still doable without.

This is only true for private households. Since 10 years ACs are widely used in a business environment.

Except, modern AC is pretty efficient. I have a decent monoblock cooler in our apartment in Berlin. I also have a 1-second sampling power meter. The AC unit uses about 700 watts when active cooling, but of course it cycles so that's not all the time. We also only run it when it's 30+ during the daytime.

Overall, it's only added about 15-20kWh to our monthly usage. (2-person household, about 200kWh/month average)

Which brings us back to the original question:

> What on earth are people spending electricity on?

It's exactly that. An AC, probably one additional appliance among others, adds another 10% to the total and somehow we manage to frame this as efficient and thus the right thing to do.

That seems an entirely reasonable incremental usage. In particular when the using A/C allows you to sleep and not running it means you get too little sleep and of poor quality. When the nights at 30-35C and the humidity high, an A/C can be a blessing.

Germans should be using heat pumps for their homes anyway, it can't be beaten for efficiency. Every time I mention this there's someone who doesn't know that heat pump systems don't require excavation: they don't.

This gets you air conditioning literally for free, and you get to be the one to frown at your neighbors for continuing to burn something to stay warm.

Only if you get an air-to-air heat pump, commonly called air conditioning.

Air-to-water heat pumps still only change the temperature of water, which is practically only useful for heating.

Are they more power-hungry than heat? A window unit can be used in the room you sleep in, and if you've done a reasonable job at reducing leakage and insulation , and reducing light ingress (external shutters, etc.) can be pretty efficient. Even in San Diego with the sun bearing down on my flat we managed to have a pretty low load factor on our window AC to keep it around 24-25C at night.

Meanwhile during the summer momnths offices in the US turn on the AC to such low temperatures that one needs to put on a sweater.

Remember that when you're too hot in an office, there's really nothing you can do about it and you just have to suffer. At least you have the option to do things like put on a sweater when you're too cold. Given that, it seems to make sense to keep the office at the coolest temperature preferred by anyone in it.

I like your logic And like lower temperatures when working. The idea that someone would ask for the whole company to be set at the temperature they want and everyone else wears a jumper quite funny.

My girlfriend strongly believes this comes from "patriarchal society" and specifically a "study" that said office thermostats are set based on an old formula designed in like the 60s and that only looked at how HVAC interacted with men.

I thought the idea that offices set thermostats to an actual standard instead of just whoever cries the loudest or has the most power to be almost laughable, so I looked for the "study" she got it from. Indeed, I don't remember the details, but the governmental bureaucracy involved in recommending HVAC did actually use a formula that was obsolete and didn't consider women. However, there was zero evidence in the study that anyone actually used that formula in consideration of anything.

I don't know if it's what the OP meant but the standard "German window" is a shape that makes an AC a lot more difficult than in e.g. the US. You can't mount it in the window directly and the insulation required is relatively irregular.

https://deine-mobile-klimaanlage.de/abluftschlauch/

Anecdotally, doors within an apartment/house are also far less airtight than in the US.

(Germans take airflow in homes extremely seriously; es zieht / frische Luft! is perhaps the fundamental contradiction in the German culture.)