@Reto81
By law we are required to maintain at least 21°c, but generally, most guests are happy with 22°c.
We do not give the guests any control over it, because yes, some will turn it up to 30°c, then leave... Then when they return, it's too hot. But rather than turn down the heat, they'll open doors and windows, meanwhile, I'm paying to heat the outdoors.
If they want it warmer or cooler, they just need to send me a WhatsApp and I will adjust on my phone.
We did recently have a guest who complained to Airbnb that it was too cold. We ended up having to keep it at 28°c to avoid a refund demand. That was expensive. Particularly cheeky since that guest had booked for 2 persons and showed up with 6, then complained to Airbnb that we were attempting to demand extra money for it.
Airbnb at least contacted us to tell us they were refunding the guest, until I asked them to review our pricing model on the listing, which has a base price for 2 persons, and incremental price for additional persons. "Oh, yes, I see". So, no refund given, but the guest was expensive to accommodate because of their heating demands.
Otherwise, we get an occasional 23° guest, but the vast majority of guests are happy with 22°.