How does one correctly balance between the Building Energy Act and KfW 55, 40, and 40 Plus?

Please excuse the late reply - I had to hunt for Easter eggs :)

To be honest, I didn’t really search properly but immediately had a good feeling with the first one and trusted my gut. Therefore, I can’t even give you real criteria. Presumably, there are quite a few "energy experts" who quickly handle the formalities (Energy Saving Ordinance proof, etc.) but don’t really plan in advance. We had an engineering firm for building physics that, among other things, also handles the renovation of old buildings (half-timbered houses, monuments, churches, etc.), and in addition plans and supervises construction in terms of thermal, moisture, and sound insulation.

With such a setup, it’s definitely no pushover. And if you also have the feeling that there is genuine interest in developing the project with you early on, at least you’ve weeded out the duds.

At single-family house level, the basic topics should also be covered by a (good!) architect, but contrary to the prevailing opinion here, there are also real losers in this profession... in that case, for example, I didn’t trust my gut and had an absolute disaster.

One should therefore beware of the false hope that the promotion of the next higher KfW "fat level" by itself (or its combination with a granny flat or the like) fully covers the additional expenses required for it or even adds a little bonus on top.

Is that really the case? Can one, through intelligent planning of the house, avoid splitting it into several units and thus double or even triple the funding? What additional costs should arise except for laying one or the other line for a possible kitchen unit? The criteria for the funding are: - Closed independent residential unit (feasible due to the location of the stairs) - Own bathroom (for example, a guest bathroom is planned anyway on the ground floor) - Connections for a kitchenette The additional costs are thus totally limited. The question here is rather whether one manages to design the floor plan in such a way that, despite "fictitious" multiple units (for example, a straight stairway in the middle of the house is thus eliminated), it still looks appealing and one feels comfortable. In the end, the KFW does not care whether you remove the doors again and occupy all 3 units yourself. I see a big cost difference in a granny flat in the basement, since you then have to insulate the basement additionally.

Best do it like acquaintances - they absolutely want the 2nd KfW subsidy for their single-family house - I saw the floor plan, the staircase is just separately in a dark corridor somewhere in Timbuktu. You can do that. Best also to bend over backwards and give up wishes just to get a measly 30,000 or whatever. Go for it!

Jokes aside: No wonder why building is getting more and more expensive. I would suggest that KfW increases the subsidy to 100k per dwelling unit.

The best thing to do is like acquaintances - they really want the second KfW subsidy for their single-family house - I saw the floor plan, the staircase is just separately in a dark corridor somewhere in Timbuktu. You can do that. Best also, you contort yourself and give up wishes just to get a measly 30,000 or whatever. Go for it!

Joking aside: No wonder why building keeps getting more expensive. I would suggest that KfW increases the subsidy to 100k per housing unit.

That's exactly what I wrote: The difficulty is that the house still meets your own ideas and you don't have to give up the "feel-good character" because of the subsidy.

that one or the other line is laid for a possible kitchen unit?

Sorry if I do not go into your nonsense in more detail,

In the end, the KFW does not care whether you take the doors back out and live in all 3 residential units yourself.

... the reference to §264 StGB should suffice.

The difficulty is that the house still meets your own ideas and you don't have to give up the "feel-good character" because of the subsidy.

It wasn't difficult for us, we just built without subsidies and the house is as we wished.