House Construction Cost Estimation - Does this fit?

Since we live in the middle of a new development area and several family members are currently building, I would say that under €3000/sqm with medium equipment is not possible at least in the southern half of Bavaria and without extreme personal work. The offers I know tend to be around €3500, but they are all at most 100 km from Munich.

For a more detailed double garage with a gable roof, our neighbors received a current offer of €70k. However, a prefabricated garage with foundations and earthworks is also available for half the price.

For our region, I would estimate:
Living area: 200 sqm × €3500 = €700k
Basement: €100k+
Garage: €70k
Additional construction costs: €60k
= €930k

With outdoor facilities and kitchen, so around €1 million.

If you’re looking for inspiration for a financing amount, it would also be good to know if the land already exists and what it costs / could cost.

Land is bought and paid: 60k€ - 700sqm

I see that the garage is also supposed to have a basement.

Correct.

Who had the stupid idea of a gas heating system?

Price difference of 8k gas heating to 35k heat pump (approx.)

Price difference from 8k gas heating to 35k heat pump (approx.)

How does the difference come about? Otherwise completely the same configuration for the underfloor heating? Fireplace for gas heating - not for heat pump House connection gas - not for heat pump Chimney sweep for gas - not for heat pump Maintenance gas - not for heat pump I assume that you will have the difference in the purchase price considering all costs in the end significantly lower. In operation, gas will then be significantly more expensive. In addition, gas reduces the value of your house significantly in the long run.

Price difference of 8k gas heating to 35k heat pump (approx.)

But those are only the acquisition costs. With a heat pump, you can save the gas connection, which saves about another 2k. Then you have a difference of 25k€ - which still surprises me. Are there really no cheaper heat pumps? We had an extra charge of 18k back in 2020, I believe, but for a Tecalor THZ504, which is a combined unit with a ventilation system and quite large dimensioned. There would also have been smaller ones.

How does the difference come about? Otherwise completely the same setup for the underfloor heating?

The house builder will certainly demand payment... because the heat pump is politically desired and consequently in demand ;) I definitely wouldn't calculate below €3000, rather around €3500/sqm. Plus basement €80-100k

Plot is bought and paid for: 60k€ - 700sqm
Correct.
Price difference of 8k gas heating to 35k heat pump (approx.)

but a current daily newspaper is still within the budget - right?

No matter how cheap the gas heating is to purchase, it is neither more cost-effective over a medium term nor (I see you have planned a children's room) explainable to the next generation.
I wouldn’t want to think about a "resale value" of the house when building new, but I would NEVER put a "ticking time bomb" in the form of a gas heating system into my house.

I would rather omit luxury (garage, etc.) and instead invest in a passive house, plus energy house, insulation, modern heating and control technology (smarthome). These things are usually not retrofittable with reasonable effort.

The metal thing can also stand outside, that’s what it was designed for! Or under an inexpensive carport.