Bedroom too warm - despite the heating being off

Right, it was the same in my condo. At the beginning, the thermostats of the [Arbeitszimmer] and [Schlafzimmer] were connected to the wrong actuators.

I know the dilemma that you can only sleep in darkness and quiet, I feel the same way. For us, it is like this: we sleep in the attic and the bedroom is the only room on that floor, so we heat very little up there and in winter it is perfect for sleeping. Dark, quiet, cool (until summer comes and because of the tropical heat you have to open the windows, then of course you hear the surroundings again... terrible). I think in your case only a thinner blanket helps. Opening the window is not an option for you (and it makes no ecological sense at all if you heat the adjacent rooms), and air conditioning would not be an option for me because of the environment. And give yourselves 1-2 more winters to get used to it.

16 degrees will almost certainly not be possible. If you keep the window always tilted, you will have nice dark spots above the window after 1-3 years.

Adjusted bed linen/equipment is the only thing that helps reasonably here, because no one sweats at 20° room temperature. I am also someone who sweats quickly, sleep in boxer shorts and a T-shirt and have a 500g silk blanket, works wonderfully.

Down blankets, terry covers, thick pajamas, etc. you can already go and throw away.

If you don't want to lose the cozy factor, there are special weighted blankets for covering up. If I understood correctly, they are supposed to be pleasant for sleeping due to their weight and improve sleep quality, but at the same time not overly warm like e.g. down blankets.
Best regards, Kati

There is all sorts of things... you could also lay me down to sleep on the median strip of an 8-lane highway with a towel.

There are all sorts of things... you could even lay me down to sleep on the median strip of an 8-lane highway with a towel.

Funny, I actually have a huge blanket on my bed that’s about as thick as a towel, and then a regular quilted comforter. I usually sleep under both and find it cozy, but I only wake up under the "towel" blanket. Apparently I get too warm at night and regulate it myself while sleeping. :D