Funding feasible or realistic

For 220 you get the shell with the roof. Ok, just kidding but you're easily missing 150,000 euros. Unless you do almost everything yourself.

The 220k for the house was calculated by the developer.

Yes, of course. They want you to sign the construction contract. If they quote you 280,000, you will shy away.

Of course, we don't have a construction service description yet, as we are still at the very beginning, but we are aware that the devil is in the details.

Why of course? Many house-building companies have their construction service description linked online... one can also expect to receive the construction service description from the general contractor after the personal meeting if interested.

With this sentence, one should actually be seen off:
“Read everything carefully. If you have questions, feel free to call us. And by the way: on your side, you still have to reckon with x, y, and z. Look at my calculation here, so you know what you still have to budget on your side in the end.”

The stated price was calculated for a solid variant with KfW55 standard, air heat pump, solar on the roof, central ventilation system, underfloor heating throughout the house, adaptation of the floor plans, and special requests in the bathrooms.

Without floor coverings, few sockets, no terrace, entrance platform, or driveway...

Yes, of course. They also want you to sign the contract for work. If he quotes you 280,000, you’ll hesitate.

Why, of course? Many home construction companies have their scope of work descriptions linked online... so you can also expect to receive the scope of work description from the general contractor after a personal meeting if interested.

With this sentence, one should actually be sent off:
“Read everything calmly. If you have questions, feel free to call us. And by the way: you still have to expect x, y, and z on your side. Look at my invoice here; this is what you still have to calculate on your side in total.”

Without floor coverings, few sockets, without terrace, entrance porch, and without driveway...

The price calculated so far has been reached through all our wishes and adjustments to the standard house.

The appointment in which the costs will be broken down and the scope of work will be discussed is approaching soon - as it has already been announced.

Topics like driveway, terrace, and a possible entrance porch are, of course, not included yet, as the framework conditions of the plot are missing here and these significantly influence everything.

The note that the desired house may perhaps not even fit the plot has also been taken into account, as that would mean a different house type.

But first, we started out with our desired ideas. You can always deviate from that, but we didn’t want to plan with compromises from the beginning.

Many thanks in advance to all involved for the numerous hints and opinions.

Best regards, Bram

For 220 you get the shell with the roof. Ok, just kidding, but it's easily missing 150,000 euros. Unless you do almost everything yourself.

Just to clarify,
the first German cost estimate for the house is 220,000€ (turnkey + walls and floors - approx. 10k) + estimated 70,000€ for the plot + 50,000€ ancillary building costs, which I count besides notary and real estate transfer tax also broker, construction electricity and water, surveying, insurances and external building experts.

So we are at about 350,000€.
I would tackle exterior facilities and garage afterwards and would also budget about 15,000€ for the garage and 15,000€ for exterior facilities. So we would still not be far above the initially mentioned 350,000€.
How do you come to the conclusion that 150,000€ would be missing? Or where would you estimate these?

Best regards, Bram

Also for Chemnitz, we are at a minimum of 450,000

Do yourselves a favor and don't sign anything as long as you don't have a property and a concrete floor plan that fits it.