Heat pump, water storage tank, instantaneous water heater, wfK, underfloor heating, heating and cooling

I think we've moved past the point of generally tinkering with the system.

Too bad.

Either invest a lot of money into the system now and reduce consumption costs in the long term or install a cheaper system now and then live with somewhat higher ongoing costs in the long term...

This is exactly where your thinking is wrong. You think you would reduce costs. But that's not the case. The house doesn't care how you produce the necessary heat energy. Keep it simple and cheap. Therefore, I'm out of here.

I have to agree with . The currently planned technology, especially the buffers, reduces efficiency, thereby increasing consumption instead of lowering it. In addition, there is a high maintenance effort and cost, as well as problems with system configuration. If you insist on that, unfortunately I cannot help.

Certainly all of this costs money, but the goal is to reduce costs in the long term.

The problem is that you generate large costs and have to finance them at about 4%. Let's say the whole thing costs you 20k extra compared to an option with only a heat pump without a chimney, then you have to save 800€ every year just to cover the interest. That is unrealistic. And we haven't even talked about the chimney sweep yet, who wants money every year. You don't save money with this; you increase your monthly burden.

Das ist letztlich auch eine Glaubensfrage.

This is not a matter of belief but a technically designable heating system for a single-family house. If you invest the money in a well-planned heat pump and a large photovoltaic system with storage, you have a zero energy cost house, or even positive.

Certainly, all this costs money, but the goal is to reduce costs in the long term.

Well, what you install today will no longer be state of the art in 20 years. We've just experienced this with our reverse cycle ducted aircon. The new one is a much more efficient system, cheaper to maintain, and costs less than what we had installed 20 years ago (same company).

Wow, the system hurts my building technology heart. Inefficiency, difficult to control, more expensive to purchase... That was a salesman and not a consultant. Just the thought that you make the hot water with the heating rod (1 part electricity to one part heat) when you also have a heat pump (1 part electricity to 4+ parts heat) says it all. Especially in summer, when the air/water heat pump has the highest efficiency. A fireplace in a house that requires 5.3 kW heating capacity in the worst case is questionable. Such a fireplace delivers several kW at once. If done incorrectly, it will be like a sauna. The water jacket prevents this to some extent, but again costs money and reduces the efficiency of the overall system (hydraulics, large buffer, system temperatures...). Control is also not great with a sluggish underfloor heating system.