Which KFW standard and which technology in new construction

Nordlys in a passive house can and should be ventilated.

To the OP
If it’s only about money, then the Energy Saving Ordinance is sufficient.

If you want to be relatively independent from energy providers someday, the Energy Saving Ordinance is not enough. If you are interested, google the blog autark mit Passivhaus. The consumption is broken down every month there.

Otherwise, Energy Saving Ordinance or KFW
I would decide between gas or heat pump once the plot and construction company are fixed.

Haydee, why would anyone want that? Autarky. Am I autarkic from Aldi, Lidl, Edeka? No. Am I autarkic from C and A, Karstadt, Ikea and so on? No. Am I autarkic from Esso, Shell, Orlen, Avia etc.? No. Why should I then be autarkic from eon or the municipal utilities?

Autarky means independence, that is what the word means. Not least from price fluctuations. I hardly drive a car, I don’t care at all whether the liter costs €1.20 or €1.60, because in total it’s not much money. That’s the reason, for example.

You can directly transfer this to heating. Gas price? It has definitely doubled several times within two years. Oil even more so. But it doesn’t matter anyway if €20 becomes €40. From €120, which I currently pay for gas, turning into €240 would be bad for the household budget.

And for some, sustainability is also an argument. I also accept that many here plan different time horizons than you have done now with the retirement home.

I already know what autarky means, I'm not stupid. Nevertheless, I think it is a stupid idea in a connected society, where everything is interwoven. But... people do it, just please don't forget that all the products that enable the so-called autarky also have to be manufactured and transported. And please also don't forget that the most sustainable form of heating is the least autarkic, district heating from combined heat and power. Karsten

The additional base fee for 2000 kWh which the heating needs is 8 euros per year. That makes 23.4 cents.

That's insanely cheap. Unfortunately, I can't get that here...

So I pay a gross 30.9 cents PLUS about 100GG.

And yes, I know that air-to-water heat pumps operate with a CROP of 1-4 (depending on AT).

But I also know that a gas boiler costs €2,800 (current project) and an air-to-water heat pump €10,000 (offer for the same project).

With the gas boiler, the outdoor chimney costs about €900 more.

Annual costs
€120/year for the chimney sweep. This is uncritical for gas since no dirt is produced.
€179/year rental for the gas tank (all inclusive)

The rest of the installation is identical. Now when I hear that I spend the same on energy costs (beautified for the air-to-water heat pump), then I can offset the annual costs of the gas heating for the next (6000/300) 20 years. Neither the gas heating nor the air-to-water heat pump lasts that long.

And yes, the underfloor heating with 10cm pipe spacing in all rooms and 5cm pipe spacing in the bathroom is quite suitable for heat pumps. Additional costs for the closer spacing about €1500 (for 320 sqm heated area and 29 heating circuits)