Is the total budget for the construction project realistic?

No photovoltaics, but probably a brine heat pump. 40+ would have been out anyway, because the battery required for it alone is already economic madness. So unless we had built with a general contractor who just happens to build 40+.

I believe what you consider mid-range standard is already upper mid-range for most here. Therefore, I find the estimate very good. The incidental construction costs are somewhat generous, but a lot will certainly be spent on the sample selection. If no misfortune occurs (bomb or dinosaur find, etc.), it is well planned.

Whether it gets tight in the end is entirely up to you by leaving out unnecessary extras.

In short, depending on the living area, a total budget of €824,500 - €847,000.

Reading that makes my stomach churn...

We have more than half in equity, even if not all of it would be available at the start of the financing, and there is enough available monthly for the remaining installments.

And my stomach relaxes again
Congratulations on this financial situation. That certainly makes building somewhat easier, even if the cost basis is higher.

Outdoor area green and grey

Nice expression - I'll remember that

Now about the KfW 40 Plus standard. We just looked at a model house with a ventilation system and cooling via the underfloor heating. That already convinced us in terms of the indoor climate. Especially since, so far, we also quite like the possibility of the KfW loan and the repayment grant.

You will also have good indoor climate in a 55 standard house.
Installing ventilation systems and cooling costs money there as well.
Without the 40 standard certification, however, you have less worries since there is no obligation to pass the inspection. That money quickly goes into even more insulation, conditions, and silly thick window panes, which is not necessarily enjoyable.

As a basement hater, I still see a basement for you: use it wisely and not just as storage rooms.

I would advise going to an architect, not a general contractor. Even if you want to build in a down-to-earth way: our user Hotzenplotz has really stretched the general contractor for his million-euro project, which someone building to standard does not always keep up with.
Some small fine things will certainly be packaged in your good standard, and an architect simply does that better.

Very good cost estimate. Neither too high nor too low. From what I gather, your expectations are quite upscale and not good standard. Building a house like that with a [GU] can be difficult. I agree and strongly recommend an architect.

So first of all, many thanks to everyone for participating so actively and quickly in the discussion of my question! This is really more than helpful. Of course, I am also glad to hear that we seem to estimate the costs quite realistically.

Yes, the incidental construction costs are rather set higher. I prefer to budget a bit too much beforehand rather than afterwards. But I try to approach this with the other cost blocks as well, with the exception of the land costs which are fixed. Anything else leads at most to trouble or disappointment during construction.

Now maybe one more question to the group. Suppose I have a house with 150 sqm of living space and a basement. How far can the price per sqm of living space realistically differ if I a) build according to KfW 55 standard with heat pump heating, photovoltaics, and ventilation or b) build according to KfW 40+ standard? Is the price difference still significantly cheaper with the 55 standard despite the above-mentioned extras compared to the 40+ house? Can someone roughly quantify this?

Technically, that means you have a 40, then it’s about the thickness of the insulation, walls, roof, and windows, etc.

From experience, you will have to add about 10,000. You get 5,000 more from KfW if it’s 40 instead of 55. That means effectively you have to pay 5,000 more.

But what’s the point? Your heating demand will only decrease minimally and it will take decades to pay off.