Best comprehensive SmartHome program

The electrician only has to connect all consumers in a star topology, e.g. roller shutters and lamps.

Exactly. But not each lamp individually, only the lamp circuits individually.

The underfloor heating is connected to the heating actuators in the control cabinet with the control valves

Nope. For simplification, the heating actuators are integrated in the heating circuit distributor.

How are the sockets connected in KNX?

Just like normal sockets.

Is every socket really connected in a star topology or do you use one 5-wire cable per room, with which you then have 1 circuit for constant power plus 2 switchable circuits?

No, only the sockets that you really want to switch individually. You think about that beforehand. The 5-wire cable approach would work like that. But there is nothing against simply assigning many sockets to actuators on speculation and then just leaving them switched on. The amount of sockets you are talking about won’t be operated by wall switches anyway. You can also simply route all socket circuits in this form into the distribution on terminal strips. Then later you can still assign whatever you want to actuators or leave it bridged on constant voltage. That would be the most flexible solution.

The electrician only has to lay the bus cable to all switches and sensors, buying and connecting the sensors you do yourself?

You can also connect all the switches and sensors yourself. KNX is SELV and therefore you are allowed to do that yourself. But something else... isn’t by any chance related to (and some others)? ;) ?

Thank you for your reply

regarding the sockets, I currently cannot imagine (I lack the experience) which sockets or whether I need switchable sockets at all.

Our electrician said right away, when I mentioned that we might want smart home, that it will be expensive because of the complex star wiring.

How many sockets have you made switchable and which ones? Should I possibly have the sockets installed normally and later switch some individually via radio or use the solution with the 5-core cable?

We also need to make the KNX installation as cheap as possible at the start and then gradually buy more push buttons and sensors and expand later

I have many sockets that can be switched and measured. This currently turns out to be more of a waste of money. I had suspected this before, but I was convinced by some forums.

KNX is not really a necessity like bread and water ;) For this reason alone, it is a waste of money or, in other words, "luxury," "comfort." Anyone who wishes may add other suitable terms. We also have a little smart home, but no sockets are currently switchable. I still can’t find a reason to want to make more than three switchable? We have supplied each room separately with 3 phases and could really make many sockets or socket groups switchable with that. But the "pressure to act" is not that high yet, or rather, quite different things are at the top of the priority list ;) And a star wiring of the consumers is not that much more expensive either, too bad the OP can’t/is not allowed to provide their own labor here :confused:

For this reason alone, it is a waste of money or, in other words, "luxury", "comfort".

The switchable and measurable sockets have simply not contributed any luxury or comfort yet. That’s why it’s a waste.
The ones that really measure active power are quite nice for finding heavy consumers (ventilation, refrigerators, heat pumps, ...).
It’s kind of funny to "measure" whether the TV is on and thus control the blackout.
Unfortunately, it doesn’t work because the OLED often continues to consume power after being turned off for the refresh.
Then you sit in the dark for another 15 minutes. :-(

And a star wiring of the consumers isn’t that much more expensive either, too bad the original poster can’t/isn’t allowed to provide any DIY work here :confused:

Yeah, you can definitely do the cables that way.
But then you quickly get a larger control cabinet, possibly more fuses, possibly more RCDs, and the actuators are added.

Yes, KNX is definitely a luxury that one indulges in.
Nevertheless, when building a house (at least we) have to watch the money.
The electrician described the star wiring as a very big effort, for which he needs much more time.

too bad that the OP can't/isn't allowed to contribute own work here :confused:

We can contribute own work, but unfortunately only AFTER handover and thus completion of the house.
We can install additional sockets ourselves and mount the switches and sensors ourselves and possibly lay the bus cable over short distances.

For the conventional electrical installation, we wanted to do some sockets ourselves (e.g., expand from a double to a quadruple socket, or possibly chase a small route and place another socket).

From your messages, I read that switchable sockets are actually nonsense, or did I misunderstand that?

yes, the TV was also my only idea for the socket but with OLED it seems that’s off the table.