House construction planning: solid house or prefabricated house? With or without a basement?

Everything is possible. However, most of it depends on the plot of land and the budget. We don't know either.

Please seriously start looking for a plot of land first. Most people are very driven by inner desires and external influences when it comes to their dream plot. In parallel, talk to your house bank. Your dream house will easily cost over 550k including incidental costs - more like 600k. However, that is without the land and development costs. If the bank gives the green light for the house and the financing amount, buy the plot.

Once the plot is settled, what you can and may build depends on the zoning plan. It may also be that you are obligated to use district heating for your dream plot. Therefore, discussions here without a plot are completely pointless, except to give you a feeling of costs.

Everything is possible. However, most depends on the plot and the budget. We don't know either.

I'll try to describe it better again:

Budget: Planning what we want to spend including a loan €600,000 (Just the house with own contributions in laying cables and programming the smart home preparation of cables and connections for later technology to upgrade the smart home to a high standard after the house construction) The garden is to be completely designed by ourselves.

A bit more detailed:

We want "Wish"
A house in city villa design (basement, ground floor, upper floor)
Including garage with door into the house

Basement: room for technology and several storage rooms that can possibly also be used differently, such as a utility room (laundry chute from the very top to in front of the washing machine), technology shaft from basement to upper floor for all lines.

Ground floor: open living dining cooking area, large hallway, guest room and base room with shower on the ground floor
Upper floor: large hallway, bedroom with dressing room and large bathroom with bathtub and shower, 2 offices with space for desk, office equipment and a couch, i.e. a cozy corner.

Outdoor facilities are to be gradually built by ourselves to consciously spend holidays and leisure time that way
The technology in the house is only to be prepared, partly also by own contribution.
The finalization of the smart home for everything related to network distribution, audio and video distribution is to be done gradually by ourselves.

The house should be designed as follows upon moving in: built-in furniture everywhere where there would otherwise be cupboards, walls and floors as well as kitchen and bathroom finished. The smart home partly finished by ourselves so that sockets, switches and lights work. (Here, one should expect more rather than less)
Everything concerning audio, video and network should be completed in terms of cabling. The then following high-priced things like speakers, amplifiers and technology behind it are to be gradually procured and programmed by ourselves.

The total walkable area of the house including usable and living space such as basement and garage should be 250 sqm.

Does anyone have any idea what kind of "gut-feeling price" one could get this done for?

We have absolutely no realistic idea what we are financially facing.

Because we retrofit the technology ourselves and program it on our own, quite high costs are eliminated.

Just for the heating and ventilation system, I estimate based on what I've found around €150,000.
Only the estimated costs for the building and cables as well as floors, walls, bathroom, and kitchen are missing.
Possibly the built-in furniture, but we have an approximate price of an additional €50,000 for the house size without the kitchen. (Normal built-in furniture for the whole house, wardrobe, living room, bathroom, guest room, walk-in closet)

If we are at €200,000
Building without equipment how much would one have to roughly calculate for 250 sqm?
How much for a normal, nice but not luxurious equipment? 2 bathrooms, kitchen, floors, walls...

2500€/sqm for the living area, I don't know about the basement/garage. If it were 200sqm living space, that's 500,000€, plus your 200,000€. Then comes the basement and the garage.

We are also doing the garden design as [Eigenleistung (EL)], but that is a lot of work and the material also costs money.

I think you really have no idea how much even the simplest sanitary equipment costs. Here in Brandenburg for 2 small (2sqm, 8sqm) bathrooms including piping, just under 12,000€. We went to the bathroom exhibition, watched the money and ended up (also due to incomplete information from the seller) at 10,000€ more. We have now reduced that to 5,000€ more but that is also no luxury, we have no concealed fittings, no super fancy rain shower, only with the toilets did we spend a bit more.

We are doing all this right now and everything is more expensive than expected and wanted.

From what I have read here in the forum so far, 600,000€ for such a large house will be tight.

You didn't even consider undergasse's objection - do you know that as a private person you don't get access to the software etc? That makes [Eigenleistung (EL)] in that area also at risk.

Sonos is multiroom for you at the highest level? Ok.

Strong. Since 2010 I have been professionally involved with Control4 among other things. Are you a dealer? Because if not, as an end customer you don't get access to the products and especially the software at all. And what do you have in mind there? Purely out of interest... MoIP or HDBaseT central?

How much would you have to calculate for a building without equipment at 250 sqm?

Normal equipment house without luxury frills in almost all parts of Germany 2000€/sqm. More like 2200€/sqm = 550,000€ just the house
+ additional costs 50,000
+ basement 70,000

= House without frills, like smart/home cinema etc. you are at 670,000

In addition comes the plot and development costs. I had already tried to indicate this above.

Sonos is multiroom at the highest level for you? Ok.

No XD this is the current state and is supposed to be replaced by passive systems ^^
I just wrote down what we have right now.

I am quite satisfied with it.
But for the house planning, it’s really something different.
Since we want to use Control 4 here and then everything central.
At the moment, it’s more central from the living room distributed to 3 TVs.
But in the house, it should no longer be like that.
Since we are renting now, it was a good start to use multiroom TV and audio.
Of course, in the house it should then be properly central, connected step by step after the house is built and beforehand the wiring should be laid to upgrade the most expensive part gradually.

Strong. Among other things, I have been professionally involved with Control4 since 2010. Are you a dealer? Because if not, as an end customer you don’t even get access to the devices and especially the software. And what do you have in mind? Purely out of interest... MoIP or HDBaseT central?

No, I’m not a dealer, but I know where I can get the equipment.
(A company from Berlin)
I only know that this system goes in the direction I imagine.
Since I know that we are talking about the more expensive devices, they are supposed to be retrofitted gradually and not purchased all at once :)
If you are already talking about Crestron, I understand on what level of knowledge you might be operating.

Certainly, you know more than I do, but I have dealt with it enough so far that I dare to continue.
The smart home we have now is also self-built.
And the new one is just one step further :)

At least there are always ways to get all the devices you want.
There is a home cinema company from Berlin that deals exclusively with this, where you can also only buy the devices, and if you really can’t get forward, they will of course help for a fee :)

But since this is a hobby and a lot of passion is behind it, I’ll definitely tackle it myself.
And even if I can’t throw around a bunch of technical terms right now, I have enough knowledge and fun with the thing to get it done.
That doesn’t mean I know everything by heart :)
Knowledge is famously just knowing where it is written, where to look, or whom to ask.

At least I want to save the costs by doing it myself that I can then spend on technology in the end.
And if I do need paid help here and there, that’s not a drama either.
It is supposed to grow step by step anyway, so I don’t need millions all at once XD ^^

Budget: planning what we want to spend including credit 600,000€

Just to clarify again. My brother-in-law is just starting to build, but in Bavaria: 180 sqm living space + basement - turnkey 580k (good normal standard) - additional costs 50k = 630k > 600k

That is not 200 sqm living space, there is no KNX, no garage or other paving work included, no kitchen or furniture, no solar system or anything more elaborate and of course no land.

This just doesn’t work at all. So first find a good plot of land and then align wishes and budget!