Ventilation in the insulated attic

I have, regardless of the thread starter, my controlled residential ventilation also in the attic. However, both the rafters and the attic floor are insulated (so double). The attic is unheated, and is ventilated at a very low level by the controlled residential ventilation, so whenever you go there, the air is pleasant, and there is no mold or anything else. It is frost-free there and all stored items have so far (well, a little over a year only) been in very good condition.

However, both the rafters and the attic floor are insulated (so double). But the attic is unheated,

That is also my plan, because of the controlled residential ventilation system that will be installed there.

and it is ventilated at a very low level through the controlled residential ventilation system

So, have you installed both exhaust and supply air in the attic, or can this somehow be adjusted via some flaps on the device itself?

One time exhaust/air supply, on different sides (better ventilation), but valves closed wide.

It depends on where the airtight layer is located.

In our case, the collar beam layer is fully insulated and airtight sealed. The attic is only insulated with 60mm wood fiber insulation.

The controlled residential ventilation system is also located in our attic, which is otherwise not ventilated – so not a classic cold roof (basically a planning and execution error). I also plan to use the ventilation system for ventilating the attic, but no supply air, as it is tempered and contains humidity (enthalpy exchanger present).

I am rather aiming that fresh air flows in through leaks in the roof and masonry, thereby preventing the risk of mold.

Depending on how cold it gets in the attic, I will stuff in about 120mm insulation and loosely secure it with foil – but I will observe this for 1-2 winters first.

The controlled residential ventilation system is also located in our attic, which is otherwise not ventilated – so not a classic cold roof (basically a planning and execution error). I also intend to use the ventilation system for ventilating the attic, but no supply air, because it is tempered and contains moisture (enthalpy exchanger present).

Did you insulate the controlled residential ventilation unit and the ducts? Otherwise, the warm indoor air will condense on the cold ducts and you will have a very good breeding ground for mold.

Of course
Although the device itself is insulated - hoses and distributors have additionally been insulated.