Upgrade from KfW 55 to KfW 40+

What you should not forget or factor in are the additional financing costs if you do not pay for the house with equity. Despite the low interest rates, for example, €6,000 in extra costs means about €3,000 more in interest, so in total you are already at €9,000 more. At least, that’s what my calculation showed, the result of which also surprised me a lot.

By the way, we don’t yet know whether KFW 55, KFW 40, or no KfW at all. I think almost everyone faces this decision. Unless you build with companies that simply clad the house with a lot of petroleum, which is sold as KfW 55 standard and thus "ecological" [emoji6]

For me, the crucial question is when something like this makes sense?

Ultimately, that is hard to say because it is complex.

One compares a few euros of energy savings per year. But that is too simplistic. No one considers that a lower heating load also has to be served, i.e. spending four figures less on the heat pump, four figures less on a borehole if a brine heat pump with probe is desired.
It is exactly like the heat pump vs. gas discussion. Gas is currently very cheap in consumption, but the system comparison often does not take into account the chimney and space requirements. The former is also fine if you still want a stove. If you don't want this, you save four figures again with the heat pump system because the investment in the chimney is eliminated. There is no need to argue over a few euros for the chimney sweep.

Hello Roppo,
for KFW 55, for example, a controlled residential ventilation system with heat recovery is not yet specified, and if you need all of this including photovoltaics, storage, etc. on top, 11,000€ can never be correct or did I misunderstand your statement "Was die ganze Technik anbelangt, die ja am ehesten dazu neigen könnte frühzeitig das zeitliche zu segnen, die ist bereits komplett in meinem KfW 55 Haus verbaut"?
For 10,000€ more repayment subsidy plus 5,800€ additional cost, in my opinion the package controlled residential ventilation, photovoltaics, and storage is not available...

Hello Roppo,
for KFW 55, for example, controlled residential ventilation with heat recovery is not yet specified, and if you need all this including photovoltaics, storage, etc. on top, 11,000€ can never be correct, or did I misunderstand your statement "As far as all the technology is concerned, which is most likely to fail prematurely, it is already completely installed in my KfW 55 house"?
In my opinion, there is no package with controlled residential ventilation, photovoltaics, and storage for 10,000€ more repayment subsidy plus 5,800€ additional cost...

Yes, you misunderstood that. Although it may not be specified in KfW 55, my general contractor already installs all the technical requirements of a KfW 40 house in KfW 55. Of course, photovoltaics comes from us as an addition, so with KfW 40+ only what I wrote in the previous post is really still missing.

Thanks again for the note about the financing costs, Stefan, that is a point I had already considered. Since it is, of course, financed, the 3,000 euros interest is naturally a significant amount!

Does anyone else have an opinion on the situation described on page 1?