Autonomous room ventilation

Hello,

I am currently busy planning an extensive renovation. A major concern for me is the room ventilation.
Currently: bedroom about 12 sqm in size. 2 people consuming air. Especially in winter when the windows are closed, I feel like I am suffocating. Either I wake up at night and have to open the window for a few minutes, which disturbs my entire sleep, or I open it in the morning in the unpleasant musty air!
In winter, tilted windows are not an option, in summer it’s also relatively bad because an air conditioner will be retrofitted as well. Leaving the door open to get fresher air from other rooms will no longer be possible after the renovation (and even now it’s not 100% satisfactory). Doors with special requirements for sound insulation will be installed, which have a sealing lip at the bottom that extends when closed.

Challenge:
- Currently: sealed room, no supply or exhaust air.
- Measures must not be visible from the outside (prohibited by [WEG]), so all common decentralized ventilation systems with heat recovery on the market are out.

Since I do not have to comply with any energy-saving regulations or similar with my old apartment, I do not necessarily need heat recovery.
I have a roller shutter box in every room that I can misuse for this purpose. An Eternit plate is in front of it from outside, so openings would remain invisible. I have already considered installing a bathroom fan (surface-mounted version) or similar on this box. All fans in this category are exhaust only – I cannot find any supply air or reversible ones.
The next problem: supply OR exhaust air alone is not enough. I need both for the ventilation to work properly.

I feel like I have already searched the entire internet but cannot find compact, quiet surface-mounted fans available in BOTH supply AND exhaust air versions. My idea was to install one far left (blowing in) and one far right (extracting out). I am aware that this is not optimal. However, despite a "ventilation short circuit" in the roller shutter box, there would be some mixing with fresh air, and in the room, I could maybe "direct" the supply air a bit. The whole thing could be time- or sensor-controlled.

Where can I find the appropriate hardware or has someone already faced the same problem and has a better suggestion?

Regards Alias_HD

One of the two does not need a fan, but only an opening.

Perhaps a window rebate ventilator would be the right choice?

Doors with special requirements for sound insulation are installed, which have a sealing lip at the bottom that extends when closed.

These are also available with an overflow function (e.g., Planet Mine drop seal), allowing cross-ventilation through the apartment. Also possibly interesting for you are Innoperform overflow seals for interior doors. And there are a number of sound-insulated overflow elements for installation in the wall. This way, a concept can possibly be implemented where the bedroom is supplied with fresh air and the exhaust air is removed through the bathroom.

In my opinion, a shortcut through the bedroom window in and out will not achieve anything.