Ventilation and exhaust with moisture recovery?

Otherwise, plants or an aquarium can of course help - although I wouldn’t get the latter just to humidify the air ;-)

I have about 10 plants in the living area with approximately 160m³ room volume. Half of them are in larger buckets with plenty of foliage. I water them in liters, not milliliters, once a week.
Humidity doesn’t rise above 30% at 19-20°.
The room also has an open roof structure and oiled parquet; I can’t imagine that the wood absorbs so much moisture that I can’t get above 30%. Even if it did, eventually it would become saturated...
I ventilate manually by opening and closing the window once a day.

I once tried humidifying the room experimentally and got up to 40%. If it should be more than that or kept constant at this level, I would probably have to do it throughout the entire apartment. Otherwise, the moisture "evaporates" into the rest of the apartment.

Hm, that is really very dry. And I would almost disagree with Lumpi there. If it were that dry because of the controlled residential ventilation, okay, then try with moisture recovery. But if you don't have any ventilation at all... Apparently, there is no moisture at all that can be recovered. We currently have only 30% in our shell construction (timber frame) as well. But no one lives in it yet, hope it will get better. It is also currently a very dry weather.

Oh, I thought this was about a hypothetical problem. If you air by hand once a day and the house is that dry, something else is probably wrong. In our still apartment, we also air by hand once in the morning and have 45-50% humidity... just as it should be.

Honestly, I don't see it as that dramatic. I also don't think that something is really wrong. After all, where else should the moisture come from? Outside, the humidity is currently not more than 40% RH, so ventilating only gets me a little more. Then I live alone, so body emissions never really make a relevant difference. After cooking for a long time, it's a bit better, but only for a few hours. The power of plants also seems overrated to me; it might make a difference, but not really much. I simply suspect the cause is that the room is very large, has significantly more wood than normal apartments, and has normal radiators instead of underfloor heating. The only thing that might help me would be less ventilation or only when it rains. But also never mind, low humidity isn't that bad after all.

For God's sake

Don't like it? No problem at all. You can complement your existing controlled residential ventilation with a humidifier. Google "AeroFresh Plus" Great thing! Although it costs ten times as much, it looks nicer.

All the suggestions like plants, aquarium, showering, cooking come from very well-read theoreticians who have little in common with practice.

Or swimming pool in the living room, when it comes to silly ideas.

Sorry. You have to be patient for another half year. The enrollment is in autumn.

: Do you even have a ventilation system? If you do, moisture recovery alone is not enough. It only recovers the moisture already present in the air. And only about 70% of that (to my knowledge). However, if you actively humidify, you can save something through recovery because then the humidifier has to run less than without it.