How much should a mid-terrace house cost per square meter today?

That’s a pretty odd calculation with the interest = cold rent. Because as a tenant, I am not forced to build up assets of 300, 400, 500,000 EUR through repayment.

The only one who does not compare apples and oranges. You say that cold rent – money that is simply gone and not building assets – should be compared with an annuity. So apples with oranges. As a non-saving tenant, I have exactly €0 assets after 30 years. If I spend the same amount on interest AND repayment for a home of my own, after 30 years I have a paid-off home worth half a million or whatever on the asset side. And that’s an unequal comparison. It only evens out if the tenant also saves = the homeowner’s annuity. The correct comparison is therefore: cold rent to interest payment. While the borrower benefits from the fact that his interest payment decreases every month, the tenant’s rent regularly increases. And yes, you also have to save for a home of your own. But the costs for a new heating system and a new roof have to be covered by you as a tenant just the same. That’s called rent increase ;-) When it comes to the new heating or new roof (with insulation), the costs are then passed on to you on top of the usual rent increase.

Only, the equity tied up in the home brings me nothing as long as I don't sell. And if I sell, I no longer have a roof over my head. Or do I sell 2 windows when the car needs repair? Your calculation may be theoretically correct, but reality looks different. Because if you set interest = cold rent, at the current interest rates the risk of overstretching yourself is exorbitantly high. What installment should come out with reasonable division? 3,000 EUR/month? Plus additional costs, plus insurance, plus reserves for maintenance, plus saving for furniture, vacation, car... Madness.

At the current interest rates and assuming it is a relatively young family, I assume a repayment rate of 1-1.5%. This results in a payment of just over €2000. Term around 40 years. Everything is fine.

Oh yes. If the property ever has to be sold, the family has assets and can simply rent an apartment. Like any normal person and as before.

By the way, costs, insurance, savings contributions, and so on are also incurred by tenants to the same extent. If the family buys the house, no additional ancillary costs arise. At most a small savings for potential renovation work.

My calculation is not theory. It is daily practiced reality and life.

With the current interest rates and assuming it is a relatively young family, I am assuming a repayment rate of 1-1.5%. This puts the payment slightly above €2000. Term approximately 40 years. All in the green zone.

Oh yes. If the property ever needs to be sold, the family has assets and can simply rent an apartment. Like any normal person and as before.

By the way, additional costs, insurance, savings contributions, and so on are also incurred by tenants at the same level. If the family buys the house, no additional incidental costs arise. At most, a small savings for potential renovation work.

Yes, that's how I know it too and that's how I calculated "rent vs. repayment" for myself as well

For new builds, 3000-3500€/sqm is often estimated here in the forum for new constructions. I suspect that terraced houses are somewhat cheaper. But by how much?

Not necessarily. What makes it cheaper is the smaller plot. Often, terraced houses have a more central location than detached houses.

Plot: approx. 100sqm Standard land value: approx. 500€/sqm according to Boris

Immoscout says: average price: 2700€/sqm for living space here in the region.

Living area: approx. 150sqm

Well, I would guess from 480,000€ to 550,000€. It also depends on whether parking spaces are available, a generous layout or window areas make the house look somewhat more modern, or if the attic could still be converted as such. Possibly, the immediate infrastructure there is poor or great.
If I check Immonet, terraced houses with about 200sqm of land and 153sqm living space start at 560,000€. But that might be due to the location. I’m not familiar with the area.

When I use ImmoScout I come across prices between 550k and 750k in Pforzheim +20 km. Deducting 10% should be realistic.