Floor plan of new rectangular bungalow with 130m² living area

A bungalow already has certain advantages (also for old age). All my "older" new neighbors have 1.5 storeys. And what do most of them do when the children have left the house? They move to the ground floor. Everyone agreed with us, it's good that you decided on a bungalow. We would have liked to build one too. Well, now they just have to make the best of it. If you like a bungalow better, then build it. It is your "dream house". :)

5th floor without elevator, greetings.

... and explains the preference for a bungalow.

kfw55 is currently not planned.

... in my view, however, a resale-friendly feature in a bungalow.

... from my perspective, however, a resale-worthy feature in a bungalow.

It probably shouldn't be a big extra effort to reach KFW 55. Since you already have a controlled residential ventilation system and presumably an air-water heat pump or a ground-water heat pump. Thus, the technical prerequisites should be met. Now the envelope/windows/doors need to be adjusted and you’re already at KFW 55. The subsidy should be higher than the additional costs.

That may be true, but after 10 years my wife can no longer stand sloping roofs, so the knee wall height increase to 1.80 in the 1.5-storey house was the absolute minimum. A bungalow would be, as mentioned above, the "dream" for us. Of course, only if it is feasible.

The KfW55 standard is certainly an advantage not only for the bungalow when reselling. Although currently everything that is even remotely weatherproof sells for outrageous prices. If it still fits into the budget, it is definitely worth considering.

My wife can't stand sloping ceilings anymore after 10 years, so raising the knee wall to 1.80 in the 1.5-story house was the absolute minimum.

But that is exactly a critical height, as I explained in the post "how the knee wall influences the window issue in the attic."

But if I can have everything on one level, why shouldn't I do that? It is simply more relaxed and practical for us.

I don’t want to deceive you, but there are also reasons why one builds a single-story house with an expanded attic:

You get more from the plot, also with regard to potential sale or further development.
Often things turn out differently than one thinks, and you might want an additional hobby outbuilding, a parking space for the motorhome, a greenhouse, a shed for woodworking or storage for something you don’t need to store yet. Maybe someday it can also be a pond or vegetable garden… the ecological aspect of sealing only what absolutely has to be sealed, giving nature more living space, and simply stating that although bungalows still have their justification, they are basically the worst thing for the topsoil.

A compact house with an expanded pitched roof also has energetic advantages.

But I don’t exclude myself, I wanted a bungalow myself... (for us, it turned into a hybrid now ;))... Fate – no, the development plan wanted it that way, and I am happy now.

What is probably rather an argument for a personality or character: many people sleep better “upstairs” :)
And you can also have some time for yourself. With stairs, you have not only spatial separation but also “the floor between you.” You don’t need to be an only child to want to retreat sometimes and where a wall alone is not enough. Ladies’ or gentlemen’s nights can be much more relaxing if the partner is not loitering in the next room, but on the other floor.

That’s why it is always worth looking beyond the standard or the “either-or”: there is not only black and white... we have already discussed quite a few bungalows here, where upstairs 2 spacious rooms, an open space or/and storage area, a large hobby room, simply more space was created, while a bungalow that simply has no roof in low-budget construction that can be (later) expanded excludes possibilities. And the bungalow that can then offer an attic expansion moves back into the more expensive price segment.
So test yourself and not just the house catalogs. A young person still has a lot of time to change and try out many things.