Construction costs per square meter of living space, experiences?

It's like with almost everything: there are rarely price limits upwards. I would also count electrical and heating among the mentioned things. For example, if someone has network cables installed in 300sqm, spots for lighting, fourfold sockets everywhere, and other gimmicks, they quickly get a hefty bill.

Envy? Analysis? They must be good friends. He hasn't even looked at my purchase agreement yet.

I really can't understand the high sqm/prices. So far, we have received 3 offers for a 140sqm solid house and are significantly below that (Brandenburg).

If you look at a Town & Country city villa, it starts at 185,000 with a gas boiler. A few extras like an additional room, underfloor heating everywhere, etc., then we're at 220,000. In the range of 215,000-230,000, two other local smaller providers have also operated; all have different wall constructions, all energy saving regulation 2016, we don't need more. That is with a 10,000 customization surcharge 1,650 EUR/sqm.

What are the providers or we as future builders calculating wrong?

You are not calculating anything wrong. Only very few people buy a Golf in the base configuration. It costs 11,000 there, but it is ordered for 40,000.

With houses, it's not such a high percentage, but doubling the standard price often happens.

And don't forget additional costs.

Yes, that is probably what it will be. My wife and I are also rather Spartan-living people. We have no high demands on aesthetics and comfort. Therefore, we will probably have our low sqm costs. We are not interested in which brand, for example, the sanitary is. Therefore, I estimate the 1650 Eur/sqm as realistic for us.

Additional costs, outdoor facilities, etc. are clearly additional.

Do you actually calculate the mentioned 2000 Eur/sqm based on this [Wohnflächen Verordnung] or according to this [DIN Norm], where, for example, sloping ceilings are not taken into account? And does the usable area also count, for example, the utility room? Or the basement?