Controlled residential ventilation: place supply air in bedrooms in the wall.

Floor air vents are common and work. We have them too. The weak draft is enough to prevent dirt from accumulating there (that means the ventilation grilles are always a bit cleaner than the surrounding floor in our case). Otherwise, I assume dust is vacuumed occasionally.

Exactly, it works... Dirt, dust, animal hair, etc. cannot accumulate there at all because there is a constant airflow... we are not here to convert you... we are only presenting our experiences and observations. The video only shows the physical principle. Of course, the effect at the controlled residential ventilation valve is smaller and not enough to make a tennis ball float, but it is enough to keep the usual house dust etc. away. Here are two pictures of how it looks after 6 years of continuous operation. They were not specially cleaned but only vacuumed and wiped wet at regular intervals... Sorry for the quality, it was just quickly snapped with the phone. Once without and once with a grille. Btw, we have two house cats... so, for example, there is really no shortage of flying hair.

Ok thanks, I will now seriously consider it, although my wife doesn’t particularly like it visually. Alternatively, I still have in mind to place the opening either next to the window or in the wall between the two children’s rooms.

With us, it is also on the floor by the windows. Because of our big boy, sometimes a small Playmobil piece lies inside, but otherwise it is similar to [mycraft] (also with [stubentiger]).

It shouldn’t fail because of the appearance; there are floor valves in the most diverse varieties (size, shape, color). If you don’t like ours, so be it... it’s only about the possibility, and a floor valve on the upper floor is IMHO the easiest/cheapest option for everyone... in other words, there are still more places where money can/will be sunk during the house construction.

This is what it looks like here: