Evaluation of Construction Project / Credit Offer

Well, setting aside the discussion about the sense or nonsense of some posts, the general tone (including mine) seems to be that all of this seems pretty tight.

2055€/month in expenses minus 140€ maintenance reserve results in 1915€/month.
With 5,200€/month income, that's just under 37%. I find that anything but exaggerated. I am deliberately leaving out bonuses, etc., because I now know how it goes: new garden furniture, awning, garden shed, vacation, Christmas, etc., all want to be paid for.

But in my opinion, there are 3 other points where it falters:

1. On the one hand, the OP here conveys the impression of an archetype of consumer greed, listing the wine cellar next to the grill hut, the 2 big cars, and many very expensive vacations, then adding that one won’t need all of that anymore in the future and wants to simplify life anyway. If you can really manage that so easily, you have my respect. I don’t want to imply anything, but I find it very hard to believe that one – especially in one of the most stressful phases of their life (building a house) – turns life upside down and gives up many things one had before and probably liked.

2. On the other hand, a 1,500€ rate on a financing volume of 500,000€ amounts to an annuity of just 3.6%. With 1.15% for 15 years, you will still have an outstanding debt of about 300,000€. That would be too risky for me personally, but that's a matter of taste. And reading the OP’s posts, he seems to be more risk-inclined, after all, he already plans internally for an inheritance...
If the interest rates rise by just 2% for the follow-up financing after 15 years (3.15% for the next 15 years fixed interest), the rate would already have to be raised to about 2,100€ to then be finished after a total of 30 years.
Again, I don’t want to imply anything, but I’m not sure if the OP is aware of this.

3. Regarding the house expenses mentioned, there have been repeated remarks that this won’t work out and it will lead to a financial bottleneck.
On one hand, because the construction costs are already considered relatively low, and on the other hand, because there is hardly any buffer for nice things.
And this closes the circle:
A building project where the above-mentioned lifestyle is lived will also want to splurge during construction and will be reluctant to give up. That’s understandable; many – including us – were the same. But you should counteract this, if you still can.

I would simply recommend you start actually living the plan from now on. You yourself said so nicely that the best plan is only as good as its execution.

Also, I would still have you request what the same houses cost under the Energy Saving Ordinance. So not KFW40+ or KFW40 and especially not KFW55. The jump here is not from 55 to 40(+) but from Energy Saving Ordinance to 55. I would be very surprised if, overall, the KFW40+ house pays off so much that it’s a clear case.

As an example: We have about 190m², built according to the Energy Saving Ordinance in 2017. Central controlled living space ventilation with heat recovery, heated with gas condensing boiler without solar.
Last year we used about 15,000kWh gas at room temperatures of about 22.5°. That’s about 900€ per year for heating – including hot water.
What is there really to save there? That’s 75€/month...

I would also reconsider the topic of building smaller; a good 170m² is better than some houses with 180 or 190, in which there are dead spaces because the floor plan is the way it is.

I don’t want to wish you (and probably most others here) any ill will. I just ask myself a bit what you actually want here? It seems to me that you have more or less made your decision anyway and just wanted confirmation that everything is okay...
Many here who answered you are already much further ahead in their planning, and therefore also their experience. That would make me think a bit if I were you.

In my eyes, you sleep much, much better with this building project if it costs 50,000-70,000€ more. Whether this comes about through a smaller house, building according to the Energy Saving Ordinance, or more equity doesn’t matter...
I recommend a combination of all three.

All the best for your project.

Apart from the fact that you never manage to write more than two error-free sentences in your posts: What are you taking to keep spouting such utter nonsense here nonstop? In every thread, it's the identical copy and paste rubbish. You’re probably dreaming of 3500€ net and living in a garden shed.

Everyone understands what Hilfehilfe means. Whether the "tone" is appropriate is another matter, but what you are doing right now is beneath contempt.

I polarize and am simply not the "nice guy". For cuddling, you should go to church or a brothel. Oh no, intermediaries are also always quite nice until the deal is closed [/QUOTE