Suitable heating system for new construction - how to choose?

Whether your wood is dry enough is already indicated by the chimney sweep. He partially tests this during his visits.

In my inquiry, it should roughly state what we have in mind. KFW55, KFW40 or KFW40+ is not so important for now, it will be one of these..

I have completely abandoned the KFW idea. I don't believe in sealing a house with insulation. Good masonry provides very good thermal insulation without "sealing" the house. That’s why I also left out a ventilation system, since we open the windows twice a day anyway. A wood stove with a ventilation system is even more complex, I would never do that. In my view, the KFW standards lead to solutions that are too complex, expensive, and sometimes nonsensical, with minimal energy savings. (You are welcome to discuss this controversially here, but it doesn't change my opinion.) The KFW loans don’t really make much sense anyway.

An air-to-water heat pump, air-to-air heat pump, or geothermal water heat pump are options.

Here in Bavaria, the bureaucratic hurdles and regulations are so extreme that air-to-water heat pumps or geothermal pumps really aren’t worthwhile. With an air-to-air heat pump, you can easily heat a 200 m² single-family house and provide hot water. If you also use a wood stove, it’s no problem at all. Moreover, an air-to-air heat pump is vastly cheaper. Especially in combination with a photovoltaic system, it’s the preferred solution. Is there a reason why you don’t want underfloor heating? It is the most efficient and comfortable heating method. That’s why it’s now installed almost everywhere. P.S.: I have consciously decided against a wood stove because it’s too dirty and labor-intensive for me. If I want the cozy effect, I would rather install a high-quality gas fireplace.

Here in Bavaria, the bureaucratic hurdles and regulations are so extreme that air-to-water heat pumps or geothermal pumps are actually not worthwhile. With an air-to-air heat pump, you can easily heat a single-family house of 200 m² and supply it with hot water. If you also use a wood stove, it's not a problem anyway. Especially since an air-to-air heat pump is much cheaper. In particular, in combination with a photovoltaic system, it is the preferred solution.

I made a typo. I use an air-to-water heat pump. I consider groundwater heat pumps or geothermal pumps too expensive and unnecessary. I would also not use an air-to-air heat pump.

A rather confusing post due to mix-ups.

Wood always releases the amount of C(O2) that it absorbed while growing.

The same applies to coal.

Regarding the environment, the timeline plays a role. If you release too much CO2 from the long-term storage back into the system in a short time, the risk of system overload is high. If you have a cycle of a few hundred years in which CO2 is absorbed and released again without the CO2 stores decreasing, you have a balanced balance. That is the difference between wood and coal. The CO2 always has the same effect, no matter where it comes from.

I have completely abandoned the KFW idea.

We have too – not because we wanted a leaky house, but because we were not satisfied with the requirements of the funds for an energy-efficient and comfortable house for us. The technical complexity of the house systems and the associated feeling of dependency also played a role, as did our preference for radiant heat sources in winter and for living with open windows as soon as heating is not needed.

since we open the windows twice a day anyway.

Isn't that quite often for manual ventilation.