Window rebate ventilator - Good idea for uninsulated old buildings?

Thank you for your answer.

So E-Strich was only newly done in the bathroom, the rest was left as is. And otherwise, only the bathroom and kitchen were newly plastered. In the other rooms, only plaster repairs were made. So I don't think there is still much moisture from the renovation. After all, everything is already about 1 ¼ years ago.

As far as I understood, I don’t need active ventilation with these, or did I completely misunderstand something?
The interior doors would definitely have enough gap and are generally very leaky, since the old doors were refurbished and are still in the house without seals.

Best regards
Specki

Thanks first of all for your answers.
I have now ordered four pieces for two windows and will test it.
Cost is 37€, that’s okay.

As I said, I am aware that I cannot completely do without airing, but if I can reduce the airing with this, that would already be very good.

Best regards
Specki

We have window rebate ventilation everywhere in our uninsulated (only the roof was insulated) old building from 1950 and find it great. No problems with mold or the like. Unfortunately, our prefabricated house manufacturer of the new house does not install windows or doors with rebate ventilation.