How high are the additional costs for a KfW55EE house?

Of course, it also depends on what is included in the €1.75 per square meter?
I would also say it could indeed be about right.

I find it somewhat low, but that may be because we already pay 102 € property tax per month. Otherwise:

- 40 € gas
- 60 € electricity
- 45 € phone, internet, IP-TV
- 18 € trash collection
- 58 € water (incl. rainwater)
- 17 € household insurance
- 28 € building insurance
- 5 € street cleaning
- 7 € chimney sweep

Such flat rates are quite nice but ultimately you largely shape your own consumption. We in the generation "lights-off-heating-off" often consume significantly less. For me, it is generally rather cool in the room; elsewhere, there are constantly 23-24 degrees or many devices are running. My former tenant in the same house as me used as much at one radiator in the bathroom as I do in two bathrooms each with 2 radiators, the kitchen, and the dining room combined.

Of course, these are only rough guidelines and one can deviate significantly both upwards and downwards. But especially when it comes to consumption values, one should consider that LED lighting is standard today and with good insulation, heating costs are quite low. Of course, if you have a daughter who likes to shower for an hour every day, it adds up. Still, many values that used to be normal can hardly be reached anymore in a KFW55 house. Example: My first apartment was a basement flat in an old building with night storage heating and instantaneous water heater and was 50sqm. Heating costs were a hefty €160 per month. Today I pay a quarter of those costs, feel much warmer, and have more than three times as much space.

I thank you for the experience and feedback. That has helped me a lot.