Construction costs are currently skyrocketing

why heat the bedroom during the day?

for daily use? Is one only allowed to sleep in the bedroom?

No child I know cares whether the window is open at night. It’s the neurotic parents who think the child will otherwise get sick, die, or something else. Children, especially teenagers, manage perfectly fine in their "muff."

I liked sleeping with the window open and so did my sister. Our eldest also insists on having it open. Anyone who wants to sleep in their "muff" can do so.

It is exactly as writes

You need 16 degrees in the bedroom to sleep comfortably under your 40cm thick down duvet. Or you just sleep at 20-21 degrees with the thin breathable blanket.

es ist genau so wie es @Tolentino schreibt

Nice when your own opinion is always the right one, isn’t it? ;) Other families just handle it differently. Don’t understand how that is so hard to accept.

it is exactly as writes

you need 16 degrees in the bedroom to sleep comfortably under your 40cm thick down comforter. Or you sleep at 20-21 degrees under the thin breathable blanket.

Thank you for knowing the sleeping habits of all Germans. Respect.
It’s not about the temperature but about fresh air. When the window is closed, my nose closes and I have to breathe through my mouth. I don’t know why that is, but it is very unpleasant.

Something is always known to be happening...

Fresh air is available even with closed windows, but this presupposes that one would have to let go of antiquated ways of thinking.