New single-family house with liquefied petroleum gas - also possible without photovoltaics or solar?

We built without subsidies; after adding up the costs, we would have been €0-3K in the plus. Everyone knows there are subsidies and it costs accordingly. This way, we could decide what and how to insulate, and we did not want a controlled residential ventilation system, but it would have been mandatory. From March to October, our doors and windows are open. The calculated savings of a controlled residential ventilation system refer to 24/365 and windows closed.

we built without funding, after summing up the costs we would have been 0-3K€ in the plus, everyone knows there are subsidies and it costs accordingly. This way we could decide how to insulate and we didn’t want controlled residential ventilation, but it would have been mandatory, from March to October our doors and windows are open. The calculated saving of a controlled residential ventilation refers to 24/365 and windows closed

We will soon take a closer look at the funding topic and may come to a similar assessment. Let’s see where it makes sense for us and controlled residential ventilation etc. is probably similar for us. I’m just gathering all conceivable information so that I can assess it as best as possible. Ultimately, we don’t have to jump on every boat that goes down the Danube, unless it makes sense from our perspective and fits our life.

Subsidies for heat pumps are and have been independent of insulation and [Kontrollierte-Wohnraumlüftung]

Controlled residential ventilation does not save money, only effort. But controlled residential ventilation can now also be subsidized if it "communicates" with the heat pump. So it may cost less than expected.

3100 at KfW 40 I find a lot. What is your annual performance factor for that?

I just looked into the info menu of the heat pump, Annual performance factor water 2.8 Annual performance factor heating 4.0, to me that's like fuel consumption in a car, sugar-coated nonsense. Our expectation was 500-800 €/year heat pump electricity costs, so that fits. We live two people quite normally, me in sweatpants and T-shirt, the better half controls the heating for warm feet. Bedroom window tilted open all night. Heating energy savers would probably manage with half, expensive (photovoltaics & co) we could certainly reduce more, but does that pay off? For us, it’s noticeably warmer "upstairs," which conflicts with having the bedroom upstairs. Regards Nida

There could still be potential with a 4 annual performance factor. But if it works for you, then everything is okay.