Architect's house in Pforzheim - Offer too expensive?

Heating fails? What do you heat with? Air and love won't warm the water in the pipes. A district heating compact station also costs money and will either be charged to you as a lump sum or, if the supplier installs it, included in the heating rate.

Controlled residential ventilation not either? Are you sure? What kind of controlled ventilation do you want to install then? Houses nowadays are so airtight that it hardly works without controlled ventilation.

Architect: You pay them anyway. For you, it's just included in the house price.

Kitchen: Are you taking your old one? Then expect adjustment costs, which are steep. We preferred to take a new one and sell the old one. It's cheaper for us.

What is your tile price per sqm? Assume that you will lay tiles.

Are you sure you like the standard in sanitary? I thought so too, and when we saw the parts live, they were just good enough for the guest WC. In total, there was another 3k for upgrading.
Count on another 10k in total for upgrades. Believe me, you will need it, like almost all of us here.

I find the price realistic - anything else is just smoke and mirrors. "Normal" equipment (with 2 bathrooms plus an additional guest WC), ceiling height at least 2.6m, I would estimate around 2000 - 2500€/m2 living space (depending on where you build). That means for 200m2 400-500 plus various extras. I hardly believe you can realize the project under 500k€. If yes, all the better. Just a note on the floor plans: What on earth do you want to do with a 30 m2 bedroom? That’s wasted space....

How much is roughly estimated for the outdoor facilities? The plot is about 1140 sqm and you need a relatively long driveway that has to be paved. I estimate about 120 sqm of paving and another 50 sqm for terraces.

For the earthworks, I contacted a deep construction company, who should make me an offer beforehand so that I don’t get any nasty surprises. But otherwise, the additional costs should be fairly well estimable if you already know the earthworks in detail, right?

for 160sqm we pay something around €2500.

That can only be the price for the paving stones. With labor and other materials, the 120 sqm paving could easily amount to around €10,000.