Energy Saving Ordinance Standard or KfW55 (without KfW)

What we definitely want is a central controlled residential ventilation system.

That already sounds very good. What else do you wish for? Heat pump? Insulated attic? What kind of wall construction? Photovoltaics?

Question: Is it still financially worthwhile to build a KfW55 house or is it much more economical to go with the Energy Saving Ordinance standard?

By the way, the plan is a semi-detached house, solid construction, about 160-170 sqm living space + utility basement + central ventilation system + triple glazing + heat pump + photovoltaic system at some point later.

55 can hardly be avoided with that.

That already sounds very good. What else do you wish for? Heat pump? Insulated attic? What kind of wall structure? Photovoltaics?

See description. I think we are probably already almost at KfW55 due to our requirements?

It's hardly possible to avoid 55 with that.

If I understood correctly, the only thing probably missing for KfW55 is the 36.5 cm wall + insulation?
What additional costs can be expected here compared to the Building Energy Act?

How is the last sentence meant?

Striking out in the sense of shortening, letting the air out. Not in the sense of painting ;-)

If I understood correctly, for KfW55 probably only the 36.5 wall + insulation is missing.

I think I remember providers of efficiency houses 55 caliber 36.5 monolithic.

Yes, the general contractors we worked with have KfW55 as standard. What we definitely want is a central controlled residential ventilation system. I also fear that deviating from the KfW55 standard probably won't make much sense or bring savings.

Our prefabricated house manufacturer did not have KfW55 as standard and pointed out to us at one or two points that since we are not building according to KfW55, we would save a few thousand euros here and there. Whether that is true, I don't know. But with the floor slab and various other points, it seems to be the case. From the beginning, we only wanted to build according to the Building Energy Act.