User-independent ventilation system in bathroom / WC or rather not?

Hello,

I am building a turnkey house and have now been faced with the following choice by the housing company:

"According to the current state of standardization and the currently applicable technical regulations, we are obliged to ensure a user-independent minimum ventilation for moisture protection. For this purpose, separate fans are planned in the bathroom and in the toilet. The single-room fans are installed as so-called 'continuous fans.' This means that the two fans permanently extract 30 m³ of air per hour each and vent it outside. The air extracted in this process flows back into the apartment through window frame vents. These are installed invisibly (with the window closed) on the window frame."

The fan can be switched to 60 m³ air extraction per hour via a switch, and there will be a humidity sensor that automatically increases the fan speed when it becomes too humid in the bathroom...

I am having an energy saving ordinance 2009 Kfw55 house built. The bathroom has a window, the toilet does not.

The question now is, do I want the user-independent ventilation with continuous operation as described above? Or would I rather have it completely off until I switch it on manually?

My tendency is not to want it, but I have no idea how loud this continuous operation is? Does anyone have experience with this and would either do it that way or not again? Or are there opinions and tips?

I would be very grateful!

...."According to the current status of standardization and the currently applicable technical regulations, we are obliged to ensure a user-independent minimum ventilation for moisture protection. For this purpose, individual fans are planned by us in the bathroom and in the WC respectively.

Window ventilation is also considered a ventilation measure (LtM) according to DIN 1946-6 ;-) For windowless rooms such as toilets, the respective state building codes usually have to be observed. In most cases, at least an exhaust ventilation is required here. Ad libitum is usually more sensible than continuous operation.

Best regards

But what about the noise development? Of course I want the ventilation system, the only question is whether it should be user-independent or exclusively operated via the switch? And should I also do this user-independently in the bathroom with a window?