Renewal of heating system in old building, which system?

YES; I do know that a heat pump and other things are eligible for funding, but I am looking for advice / tips / experience on what kind of heating system makes sense in my context. Just because a heat pump is heavily subsidized and politically promoted and is currently installed in new buildings with underfloor heating everywhere does not mean this solution makes sense for my old building (existing building). The efforts required to bring my old building up to KFW55 standard are either technically no longer possible or economically unjustifiable.

I am looking for advice from people who are in my situation (see above facts).

Best regards

I am looking for advice from people who are in the same situation as me (see facts above).

What does the expert = energy consultant say? After all, he knows the property and the conditions much better than we do here.

If 45% of the costs for [Fbz, heating, renovation work] were subsidized, I would consider a heat pump as the top choice.

Just a quick calculation: 2500 liters are about 27,000 kWh.

Heat pump with COP 4 results in between 7000 to 8000 kWh electricity per year, which is about 2500 euros per year.

If that would be acceptable for you, I would have the better insulation done from the savings.

If 45% of the costs for Fbz, heating, renovation work were subsidized, I would put the heat pump at the very top.

With GAS-hybrid with solar thermal and at least 25% heating support, it is 40%. So it doesn't make much difference.

Quick calculation: 2500 liters are about 27,000 kWh.

Heat pump with COP 4 results in between 7000 to 8000 kWh electricity per year, about 2500 Euros per year.

If that would be acceptable for you, I would use the savings to get better insulation done.

Uh, what savings? With 2500 EUR electricity costs, I would pay more than with oil currently. There it is about 1700 EUR annually.
I think with the GAS price one might also get off cheaper, right? About 1400 EUR annually.

Or am I misunderstanding something in the calculation?

Best regards

No, you are right, I had forgotten that there is also funding for gas hybrids in the existing stock.

Therefore, I would also tend towards gas here.

Savings referred to the 45% or 40% subsidy, meaning I would invest the money from the subsidy in insulation and possibly a new underfloor heating system.

But I would have that recalculated to see how much it would actually help.