Unrenovated single-family house from 1973 - Renovation or new construction?

Always happy to help. I have renovated two houses myself, albeit with a lot of personal effort. What helps when saving money is gutting. If you do that yourself, definitely factor in good tools. A cheap hammer drill, for example, is extremely heavy.
In any case, many hours of work go into that, which you wouldn’t have to pay for then. At least not if you can do it without losses at work.
I also made breakthroughs for pipes and the casing for the flush tanks, after consulting with the plumber. That saved money too.

Also think carefully about what you want. A "I'll do it later" often means "I'll never do it." Underfloor heating is an issue here..
Also consider things like roller shutters. Electric or with a strap currently? If with a strap, then maybe electric in the future? And how controlled?
Insulating the basement ceiling... an efficient measure as personal effort.

You have taken the first important steps. Keep asking for ideas and experiences. By now, there are some here who have gained experience with renovations. And not from an office but at their own property.

Pay attention to the ceiling height if you want to install underfloor heating. Is the house basemented? Then you can nicely insulate from below. Otherwise, the floor construction becomes tricky.

I am currently doing a very extensive renovation. My list says that I will end up ready to move in at around 1500€/m². But that includes everything, including floors, lamps, and the kitchen. The garden will come later.

What exactly do you mean by "my professionals"? If you do it commercially, it will probably only be calculated turnkey. I could have also done my renovation project turnkey for 1000€/m² without the new dormers and done more simply (e.g., insulation in EPS instead of mineral wool).

Anyway, the cost breakdown from the architects by trade would be much more meaningful than all the incomparable case studies. : Can you post the list here? Then we can also give better feedback.

I can confirm your experience exactly. We are also at the final stage of our core renovation in a very cheap area of Germany and do not come anywhere close to 1000€, let alone new build quality. In addition, the building structure was great (~built ~1960 / ~150m²) and we provided almost 2 years of own work (complete electrical, gutting, shell construction, painting work, drywall, etc.) and worked without an architect. We have the luxury of many craftsmen and construction engineers in our circle of acquaintances. Our rough costs were:

Roof 32k
Windows + front door 9k
Heating (3 floors underfloor heating) 16k
Water/sewage 7k
Interior plaster 15k
Electrical materials 3k
Painting materials 1k
Construction debris 4k
Natural stone 2k
Drying 6k
Screed 3k
Drywall 5k
Interior doors 6k
Tiles 14k
Floor coverings 9k
Sanitary installation 9k
Outside stairs 3k
Balcony sealing 2k
Exterior plaster repairs 3k
Building materials 7k
Home network 2k

How one can get to 1000€ per m² there is absolutely beyond me. New construction is not always more expensive than a core renovation.

Always happy to help. I have renovated two houses myself, but with a lot of personal effort.

... and I guess I'm right in assuming that your forum name didn't come about by chance

What helps when saving money is stripping out the interior. If you do it yourself, definitely factor in good tools.

And, not least, that precision during demolition takes even more time than building new. Knocking things down gently is something you should also be practiced at.

What exactly do you mean by "my professionals"? If it is operated commercially, it will probably only be calculated turnkey.

Commercial customers, e.g. residential complex Berlin with 150 apartments or similar - that is always turnkey without own contribution including taxes and including professional architectural services/construction management/accompanying construction controlling/internal fees etc. Sometimes it is €850/sqm, sometimes also €1,200. That then depends on the quality or the situation found.

Thanks also for the further answers.

A question of understanding: When you talk about gutting, do you actually mean removing interior walls? Why would you do that in a house with good substance, whose floor plan essentially suits you?

The (if I have calculated correctly) 158k from do not seem so bad to me compared to the estimated 270k for us. The two years of personal work have their value, architects don't work for free, and unfortunately we hardly have any craftsmen in our circle of acquaintances either.

Buildings with 150 apartments as described by are a different situation than a single-family house. It doesn't surprise me that they are cheaper to renovate per sqm.

: Unfortunately, I don't have a comprehensive list, just the total estimate of 270k (including taxes + architect) and a few individual items:

[*]Windows+doors 25k
[*]Scaffolding (for the following items): 3k
[*]Roof covering: 30k
[*]Roof insulation: 15k
[*]ETICS (EPS): 35k (incl. balcony)