Is basement area more expensive than living area?

We are currently building a house with a "Kellerersatzraum" of about 16 sqm interior space. The room costs approximately €14,000 including earthworks, foundation, floor slab, insulated (walkable) ceiling, exterior plaster, interior plaster Q2 etc., but without underfloor heating. We are building in the west of Middle Hesse. Just so you have an example for such a room

We are currently building a house with a "basement replacement room" of about 16 sqm interior space.

Thank you, that is a helpful example. How do you solve your storage space needs? Attic? Garage? Other?

Thank you, that is a helpful example. How do you solve your storage needs? Attic? Garage? Other?

Please. We have a guest room, which will most of the time of the year not accommodate guests, and an attic, which is not very big but can still hold some boxes or similar. And in addition, this cellar substitute room.

Above ground, I would equip the "basement replacement rooms" quite simply, but all with underfloor heating, inexpensive tiles, and paint on the walls.

Let's put it this way: 1000€/sqm basement makes 70000. Plus a bit of extra waterproofing, no idea, the usable basement might cost 90000.
If you forego 70sqm utility rooms, you plan 10sqm at 1500€ more living space on the ground floor, above that there is a 10sqm storage room.
That makes 20sqm for 30000. Should be more than enough for 4 people.
I averaged the price a bit, since the additional space is built into a house that is already equipped with HVAC, etc. However, you might want to make the children's rooms a bit bigger, since a play basement is then no longer available.
Anyway: a basement is expensive if you only use it for utility and storage space, it becomes even more expensive if there is water involved. Why one clings to that instead of making the house a bit bigger is beyond me. Not only because you don't bring lawnmowers, bikes, and the like downstairs anyway and need a tool shed above, but also the risk that the basement will eventually become damp would discourage me.
As long as it is not just about a 200sqm terraced house, you usually have the freedom to generate storage space differently.

For soil class 7 (under our house), the basement is a money pit. As always: comparability has its limits. Whether a basement or living space is more expensive cannot be answered in general terms so that the original poster can make a valid statement for their project.

As long as it is not just a 200sqm terraced house, one usually has the freedom to create storage space differently.

In this case, this is only possible to a limited extent, otherwise we would not be considering the basement so seriously. With a fairly compact floor plan, a huge usable area would be gained all at once. This is needed for various hobbies and prospectively 3 children. Nevertheless, forgoing the basement seems to be the more economical solution somewhere, even if it is associated with some disadvantages...