Forgetting ventilation in an energy-efficient house

Hello,

I am currently renovating a house with KFW funds. In the KfW application, a decentralized ventilation system with heat recovery was planned. Now, shortly before completion, it was noticed that this was "forgotten." The energy consultant says the construction manager is to blame, and the construction manager/architect says the energy consultant should have noticed this as well... So no one is at fault, but as the client, I now have some problems. Can someone tell me definitively whose responsibility it is to ensure this KfW-relevant component is taken care of?

That is your task as the builder and as a subsidy recipient of the KfW. Have you commissioned anyone to implement the ventilation? Then grab them by the ears.

The energy consultant says the site manager is to blame, and the site manager/architect says the energy consultant should have noticed this as well...

You all should have noticed this anyway. You just have to have them installed afterwards, what's the problem?!

Right now, you can also easily integrate a decentralized one once everything is finished. The question arises why anyone sees a problem there at all.

Can someone tell me with expertise whose responsibility it is to take care of this KfW-relevant component?

It depends! Ultimately, certainly the builder. But maybe the builder has concluded a contract for work, in which he agreed on a renovation including decentralized ventilation? Then he could possibly now insist on contract fulfillment.

Alone, we do not know, as you have forgotten to mention essential details ...

Thank you for your answers. In the end, it was actually easiest to retrofit these ventilation units. I was afraid that the object would have to be fitted out again for this, but that was not the case. So, for now, it's okay.