Own cost estimate - does it fit?

Hello everyone,

like so many, we are thinking about building. We roughly estimated what our project might cost in order to determine whether we want to pursue it further. The forum has already helped us through reading, now we specifically ask for an assessment of our thoughts.

Single-family house, 170 sqm, 2 floors, flat roof, simple design, KfW 55, no basement, monolithic construction, brick double garage with space for garden tools, bicycles, garbage cans. Photovoltaic approx. 4 kWp, geothermal energy with ground collector. Garden initially with necessary paving work and lawn seeding.

170*1600 = 272,000 house 8,000 photovoltaic 20,000 floors and painter 40,000 ancillary building costs 25,000 garage 15,000 garden

Makes a total of 380,000€ plus land and incidental purchase costs, furniture (kitchen), moving and the like.

Is that about right? What saving potential would there be regarding the garage, e.g., a corresponding carport? Is an air-to-water heat pump significantly cheaper than geothermal energy with ground collector (probes probably not possible)? We don't like air-to-water heat pumps much because of the appearance and possible noise disturbances.

Building location: Northern Ruhr area (Gelsenkirchen/Recklinghausen)

Would still plan a buffer of 10-15 T €.

What potential savings would there be regarding the garage, e.g. a corresponding carport?

Different material for the garage. For example, wooden studs or sheet steel

Where do you include the geothermal costs?
A reasonable double garage massively integrated into the house, about 30,000 euros.

I always think, what makes sense at the beginning or would cause much more effort and costs later on, is worth doing. If you want a massive garage attached to the house, then plan for it. You will regret it later if in 3-4 years the excavators roll in again to build the garage or if your great cheap prefab garage is already ruined.

Calculate the enclosed volume cbm.
Take this value times 2,000 euros/cbm. With that, you have a pretty good value also in regard to KfW 55 and gross prices.

What about the civil engineering work? Depending on the plot and soil survey, a five-digit amount can add up.

You can initially scratch the garden. For 15,000 euros, you won’t even get a reasonable front garden with driveway, parking spaces, and entrance.

Furthermore, scratch photovoltaics and the geothermal stuff. Plan conduit pipes in, install a reasonable heat pump, and that’s fine. You will also need a ventilation system, but you can include that in the 2,000 euros/cbm.

2000€ / cubic meter???

2,000 euros per cubic meter. A single-family house should have between 600 - 700 cbm.