Budget calculation single-family house 160 m²

Connection costs are also significantly higher if the on your property are not already available (through existing infrastructure). In Berlin: 1300 EUR for drinking water plus earthworks 800 EUR telecom (if empty conduit is available, otherwise plus earthworks) 1300 EUR electricity, 1400 EUR for outdoor pillar/connection inside the house plus earthworks possibly gas (no idea) possibly cable (min. 1000 EUR plus earthworks) Wastewater approx. 3600 EUR if work is not already being done on the sewer or if there is no existing preliminary extension plus earthworks. The earthworks can partly be done in EL and you get a discount. Or try to coordinate (which further restricts the dates). I would rather budget 10,000 EUR there

Corner windows are anyway the "retro" of 2040 ;-) Budget issues in my opinion are like counting without the host if you don't know the plot. Not only in the basement question does the plot speak with at least as loud a voice as you do, but also the soil conditions are a significant factor for the costs that must be managed even before the foundation. The development plan also has demands and can, in particular, say "no" quite emphatically (and suddenly child 3 doesn't get a dormer).

Then a standard calculation

160 sqm as KFW 40 -> 160*2400=384,000
Basement 80 sqm with heating/electricity/simple tiles/plastered -> 80*1100=88,000 (actually I doubt that you can get the basement within the thermal envelope for KFW 40)
Earthworks/excavation basement including disposal -> 30,000
Additional building costs -> 30,000
Outdoor facilities -> 30,000 (I doubt that the carport is included)
Kitchen and other furnishings -> 25,000 + x
Total: 587,000 without land
Personally, I believe that with basement within the thermal envelope, carport and later a bit more garden costs it will rather exceed 600,000.

But 160 sqm house + basement is not exactly a small house either.

preferably (flat) gable roof, because it is the most cost-effective
- KFW 40 plus, because we think due to the climate crisis that the house should be as energy-efficient as possible, then with air/air heat pump + photovoltaic

If you care about saving the earth, then the double garage confuses me.
Energy efficiency is good, very good, but just inform yourself about what that actually means.

Once someone built the entire house with everything for €350,000,

(Yeah, us... including that)

other times someone is already at €450,000 and hasn't even included ancillary costs. In short: the more we read, the more uncertain we become.

It all depends on the requirements.

But we are not married to the basement and could also imagine a utility room + technical room rather than having it fail because of the basement. So thank you for your insights!

Okay, the basement is cancelled. €170,000 without frills with own work €350,000 in 55 standard, ancillary building costs €30,000, exterior €20,000 plus carport.
In Brandenburg it can be cheaper if you build regionally and down-to-earth.
Did I understand correctly that there is still no plot of land?

You can also see that the calculation by ypg and me roughly match. For the house, deduct about 30k less for KFW 55, basement, and excavation costs, then the numbers are very similar.

Thank you for your answers.

Connection costs are also significantly higher if the on your property are not already present (from existing structures).
...
I would rather plan for 10,000 EUR

Okay, sounds reasonable!

Then a standard calculation

160 sqm as KFW 40 -> 160*2400=384,000
Basement 80 sqm with heating/electrics/simple tiles/plastered -> 80*1100=88,000 (I actually doubt that you get the basement in the thermal envelope at KFW 40)
Earthworks/excavation basement including disposal -> 30,000
Additional building costs -> 30,000
Outdoor facilities -> 30,000 (I doubt that the carport is included in that)
Kitchen and other furnishings -> 25,000 + x
Total: 587,000 excluding the land
Personally, I believe that with basement in the thermal envelope, carport and then somewhat more garden costs it will be over 600,000.

But 160 sqm house + basement is not exactly a small house either.

Okay. Basement out, earthworks removed, then at first glance we would be within your range at 469,000. Carport, terrace we can build ourselves through family in self-performed work, only material is needed.

If your concern is saving the earth, then the double garage confuses me.

Yes, well it should be future-proof for two cars, then of course electric vehicles charged with photovoltaic power... If one may dream a little.

Okay, the basement is cancelled. 170,000 without frills with self-performed work 350,000 in 55, additional building costs 30,000, outdoor 20,000 plus carport.
In Brandenburg it can be cheaper if you build regionally and down-to-earth.
Did I understand correctly that there is not yet any land?

The calculation sounds doable then, or am I mistaken? Correct, there is no land yet. But without roughly outlining our dream house, we can hardly gauge our land budget there. We are aware that if demolition etc. might be necessary there, we will need to add something, or have to go down on the house. You can only say that once you know what can be omitted from the house.

You can also see that the calculations from ypg and me roughly match. Calculate about 30k less for KFW 55 at the house, basement and earth excavation costs gone then the numbers are very similar

Yep, I like that when multiple opinions agree :)
30k less for KFW 55 at the house... that's amusingly the 30k subsidy, right?

One more thing, we basically have a gas heating + sanitary company directly in the family. Would you factor in savings there? After all, we would get everything in that area from the wholesaler at purchase price and possibly only pay for material + labor installed.

What do you think if we take the adjusted calculation from the beginning, can we classify it as "barely doable" or definitely strengthen it further, obtain offers, etc. before we can be sure we are not deceiving ourselves?

House (construction, technology)	384,000.00 €
Basement	---
Outdoor facilities	20,000 €
Furnishings (kitchen etc.)	20,000 €
Additional building costs:
Architect	32,000 €
Expert opinions etc.	3,500 €
General incidental costs (electricity/water connection)	10,000 €
Miscellaneous and reserve	30,000 €
= approx. 500,000 €