Operate heat pump autonomously with photovoltaic system.

And is there kfw in addition?

Yes, €15,000 KfW from Program 153 and up to €18,000 from the 10,000 Houses Program. Additionally, BAFA subsidies are also possible.

I am from Bavaria and want to build and have not yet obtained any offers. Is Kfw 40+ worth it in terms of the additional costs and possible subsidies compared to KFW 55?

I am from Bavaria and want to build and have not yet obtained any offers. Is KFW 40+ worthwhile in terms of additional costs and possible subsidies compared to KFW 55?

No, very likely not even despite all subsidies.
You save - depending on the house size - about 10 - 30 euros/month going from KFW55 to 40+. WITHOUT factoring in necessary capital costs. Rough estimate. Even KFW70 (now Energy Saving Ordinance 100) requires very little energy, KFW55 accordingly a bit (but not noticeably) less, 40 and 40+ are already a minimal league. At a hefty premium. 40+ requires the most complex solar systems with generously dimensioned batteries. That is still damn expensive nowadays.

However - technically speaking, KFW 40+ is indeed something great.
Do you have the money? Do you want to tie up capital for the sake of technology, fun, and environment? In your house. Without directly benefiting monetarily in a noticeable / significant way?

Then do it. If I had been able to, I would have done it.
For the sake of fun - and because a machine room like an aircraft carrier seems strange to me as a physicist in a house, but not frightening.

Regards
Thorsten

Thank you Thorsten for your assessment. KFW 55 compared to Kfw 70 might be more worthwhile?

When I built back in 2014, KFW55 would have cost me about 12-16 thousand euros more.

Let’s deduct about 8 thousand euros for underfloor heating, which I didn’t want and never want to have.

My problem in "", or rather the preferences of my wife and me regarding heating.

For say 8 thousand more, it wasn’t worth it to me or the bank to finance the additional effort, which would have mainly been in the foundation slab and groundwork (my KFW70 is almost a KFW55, very close).

The Energy Saving Ordinance 100 (KFW70) costs about 10-15 euros/month more in direct heating consumption compared to 55.
Even with a KFW70/Energy Saving Ordinance 100, on about 130sqm including heating and hot water, you’re already at (whether gas or air-water heat pump) 50/month. The margin to save is getting slimmer and slimmer.

Only: If I had already known then that KFW70 is a phased-out model and would become the standard in 2016, I would very likely have built KFW55 solely for market/resale value reasons.
Today I would therefore build KFW55, it currently seems the most sensible to me. KFW40 and 40+ are amazing, but enormously expensive.

You can quickly end up 10-30 thousand euros higher here than with KFW55.

Best regards
Thorsten