Cold despite 20 degrees air temperature

Friends with a new Kfw40 house with a heat pump have 18° in the bedroom and 21° in the living room. Of course, the bedroom door must remain closed.

It also strongly depends on whether a ventilation system is installed and how many windows the house has and and and

it also strongly depends on whether there is ventilation installed and how many windows the house has and and and

I can hardly understand that either. We have a lot of glass and ventilation and yet large temperature fluctuations between the rooms can be realized.

Hi,

so... just wanted to give a quick update. With all the nice tips here (ventilating and heating) I have now achieved a constant humidity level of max 45%. I always heated well (sometimes up to 23 degrees in the bedroom). I didn’t ventilate for a day just to see what would happen. Even then, the humidity didn’t rise above 45%. What totally confuses me now is the following: The bedding in my bedroom feels clammy, even though the humidity is 43% at 21 degrees. When I sleep, I start to sweat after a short time. I mean, nobody needs to sleep at 21 degrees. 18 degrees are totally enough. But why does the bedding seem (or is) clammy at these values?

or could it possibly be because the moisture-saturated air is still settling on the furniture?

Your hygrometer is incorrect.