Is KfW40+ possible even if photovoltaic and controlled residential ventilation were already required for KfW40?

Hello,

the requirements for KfW40+ are - simplified - as follows:
- KfW40
+ Installation of a photovoltaic system
+ Installation of a stationary power storage system
+ Installation of a controlled residential ventilation system

But what if you are currently at KfW55 (without controlled residential ventilation) and, besides the photovoltaic system (which is going to be installed anyway), only a controlled residential ventilation system is needed to reach KfW40?

Is it necessary for KfW40+ that the KfW40 standard is already met or could be met without measures from the Plus package (photovoltaics, storage, controlled residential ventilation)?
Could the KfW possibly be a bit strict in this regard?
Otherwise, for me, practically only the controlled residential ventilation system + storage would be necessary to jump directly from KfW55 to KfW40+.

KfW 40 is not about a zoo of equipment but about the quality of the energetic envelope and the efficiency of heat generation. As I understand it, only the photovoltaic storage is then absolutely required for the Plus, but the rest is probably not necessarily needed (although usually hard to do without in order to reach the goal).

Your outer shell only meets kfw55, nothing more. To even achieve kfw40, you need a different outer shell.

Which insulation values you need for the building envelope are influenced by various factors and part of it is the bonus from the photovoltaics. For heat pumps, I believe there is also a bonus. Depending on the existing wall thickness, sometimes that's already enough (e.g. Ytong 42.5) or you have to insulate a bit more under the floor slab (in our case, Ytong 40cm). The photovoltaics then of course also count for 40+

Which insulation values you need for the exterior shell are influenced by various factors, and part of it is the bonus from the photovoltaic system. I believe there is also a bonus for heat pumps. Depending on the existing wall thickness, that is sometimes enough (e.g., Ytong 42.5) or you have to insulate a bit more under the floor slab (in our case, Ytong 40cm). However, the photovoltaic system also counts for 40+ of course.

These are independent values. The two values for technology and shell (primary energy and final energy demand) do not influence each other.

Exterior walls, windows, insulation, ceilings, floors, front door are one value.

Heat pump, photovoltaic, solar, controlled residential ventilation, solar yield, etc. are another value.

Both values have limit values that must be met for KfW55 or KfW40 respectively.

Ok, then I misunderstood something there. But no matter how that is fulfilled is the problem of the GU, I definitely ordered 40+ ;)