20% humidity in KFW 40+ new construction

9% was then the decisive reason

Okay, but 40° is not a problem? :D

In the sun, that is actually not so much. I estimate that corresponds to about 24°C in the shade?

In the sun, it is actually not that much. I guess that corresponds to maybe 24°C in the shade?

One should keep in mind when displaying the relative humidity that it depends on the temperatures and is then distorted if the sun is shining directly on the sensor, right?

Yes, that's right. 9% at 39°C corresponds to approximately 20% at 24°C. ~4.4g/m³

Fortunately, we have air conditioning. When the hygrometer is in the shade, it is about 24 degrees. But it does not feel that warm to us. According to the display with air conditioning, we have 24 degrees, but it is so comfortable and sometimes even cool. KNX switches, hygrometer, and air conditioning all show the same value: about 24 degrees.

The low humidity causes another problem: electric shocks! We keep getting them from our chairs. In the old house (also tiles) that was not the case!

Yesterday I had the humidifier on in the bedroom. Full blast and the door closed. I fell asleep while putting the child to bed. At 11 pm the smoke detector went off at 85% humidity... Never happened before... It’s just annoying.

WHEN is the EWT coming????