Now the houses from the providers are crowding all real estate portals and advertising with included land and turnkey.
Prefab house (solid).
I don’t know what you mean by prefab house solid,
but if I assume that you mean exposés where house construction companies present a house and refer to a specific plot of land, then the companies often align themselves with a new development area and reserve plots. In this case, Heinz von Heiden, Viebrockhaus, Town & Country, and all the others often refer to the same plots sold by the municipality (no tied sale). However, there are also offers where the construction company acts as an intermediary and/or possibly as a developer. Then it is either a tied sale, even though you are the builder and must pay property transfer tax on everything. Or you buy house and land from one source and then also pay property transfer tax on everything. Buying from a developer means that they are the builder and you are just the buyer.
House construction companies can and do both. So it depends exactly on the offer.
One is higher quality, the other cheaper, referring to the house (construction method and fittings, this is stated in the construction service description).
The cheaper one has cheaper fittings and construction. You then pay more for a better standard on top of your standard; better providers do not need as much upgrading.
What is almost the same everywhere if you build as the builder:
For example, earthworks from 30 cm depth, ancillary construction costs, utility connections, more sockets, and high-quality tiles.
And: painting work and floor coverings in living and bedrooms.
Later come the exterior facilities and carport/garage.
The difference is that a low-budget provider installs tiles at €20 each and a 200-liter hot water tank, while the more expensive and better one installs €40 tiles and a 300-liter hot water tank.
Example: we built with a regional company comparable to Heinz von Heiden.
Our friends built with Viebrockhaus. Their house was about €30,000 more expensive in the basic configuration, but with the Nibe pump and KfW55 standard, but only decentralized ventilation. We use gas. We had to upgrade to KfW70 standard with controlled residential ventilation in the five-digit euro range.
In terms of floor coverings and additional features like level-access shower or electrical work, we roughly paid the same as the craftsman.
So: 2024: catalog price plus basic updates plus good average fittings
-> €3000/sqm living space.
Ancillary construction costs extra (plot-related €35,000-70,000)
Exterior facilities €20,000-50,000 (rough guideline)
Kitchen and so on.
You usually do best by choosing regional construction companies and finding your own plot beforehand. However, there are regional situations where this is hardly possible anymore.