Which smart home system to retrofit?

The developer told me that the topic of Smarthome must be discussed entirely with the electrician

what would be the optimal solution to ask the electrician if he can/wants to implement it this way and at what price

What would you estimate your proposal would approximately cost, so that I can assess whether the price offer is realistic or much too expensive

The system should also be adjustable and programmable by me later without having to hire a professional

what would be the optimal solution that I should ask the electrician if he can/wants to implement it that way

What is the optimal car based on the statement "I want a car with an engine, steering wheel, 4 wheels, and seating"?

What is the optimal car based on the statement "I want a car with an engine, steering wheel, 4 wheels, and seating"?

Tata Nano :cool:

Tata Nano :cool:

Then like this: What is the optimal car based on the statement "I want a car with an engine, steering wheel, 4 wheels, and seating that optimally covers my individual needs"?

Otherwise, I would probably just answer Shelly or Sonoff here and be done with it.

I completely agree with the previous speakers. The car examples always apply very well to home electrical systems. Should the heated steering wheel be included or is the automatic tailgate enough?

The builder told me that the topic of Smart Home needs to be discussed with the electrician

Correct, we have already advised you several times here. That is the usual way.

what would be the optimal solution that I should ask the electrician if he can/wants to implement and at what price

Only you can decide that for yourself. Optimal would be a structured wiring. Separate and secure communication. Open system without vendor lock-in. Stable on the market and looking to the future. Without constant updates because some 14-year-old found a security hole again and wants to exploit it. Without cloud but still with full external control... quickly adaptable (without three years of study and knowledge of programming languages etc.) to new needs and/or new residents and/or new technical possibilities... and so on.

What would you estimate the cost of your suggestion to be, so I can judge whether the price proposal is realistic or way too expensive

10-100 thousand... anything else would be grossly exaggerated.

The system should also be adjustable and programmable by me later without having to hire a professional

Yes, it certainly should. But that is true for most common systems anyway.

I have now tried again to read up on the difficult topic

From what I have read, KNX is supposed to be one of the best solutions but very, very expensive (at least 10-15 thousand euros) and very difficult to install and program.
For changes, you often or always have to call an electrician (unless you have extremely good programming knowledge).

What do you think of Busch free@home? It is based on KNX and even uses the same cables.
It is supposed to be cheaper and easier to program (thus designed for private users).

The disadvantage is that everything comes from one manufacturer, but it is a large one Busch Jäger.

Would Homematic IP Wired be an alternative to Busch free@home? Both systems come from only one manufacturer.

We had imagined having to spend max. 5000€ now for smart home (preferably less), but if cables have to be laid, you have to do that immediately.