BlowerDoor test mandatory for ventilation system and KfW70

Hello dear forum members,

the title actually says it all.
We are building a Kfw70 house and have decided on a ventilation system with heat recovery for comfort reasons. Are we obliged to do a BlowerDoor test? Or should we do one in order to properly adjust the ventilation system at all?

Hello,

as far as I know, a blower door test is only mandatory if both a controlled residential ventilation system is installed and funding is applied for - that is, as a basis for the subsidy.

Otherwise, a BDT is more of a "nice to have," which many construction companies now provide as a "quality feature."

Regards,

Dirk

...because a BDT shows the holes in the building through which heat can escape

Only necessary for funding... otherwise not...

Hmm... so we do have to make one after all, because we took the KfW70 loan and thus have funding.

That's how it is
But don't you want the test? After all, gaps in the envelope can be identified... That is important for the heating season