Experiences upgrading a smart home in a single-family house

Not even if both use the same protocol, that would have been my expectation here, that it works? Otherwise okay, I need a layer on top.

No, not always even then. A lot is always promised, but in reality it turns out that if you stay within the manufacturer's own ecosystem, you have full functionality. However, as soon as other manufacturers come on board, you sometimes only have basic functions left.

I have looked at the sources you cited (or rather my Google results on them: cradle-mag, baubiologie-magazin, ibes-gegen-elektrosmog). The first sentence appears three times almost identically and without further explanation. I also find the second quote in "pc-magazin," which is not known for good research, along with the sentence "Die Aufgabe von Bluetooth und WLAN ist es, Kabel durch Funk zu ersetzen. Deshalb müssen sie immer aktiv - sprich: on air - sein." The latter is obvious nonsense. Again, I find the statement in a book by Günther Ohland, preceded by the sentence "Der Gebäudefunk an sich ist für die Gesundheit unbedenklich." There are different views on electrosmog, but the statements you cited can probably be ignored. It is rather a very personal yes/no assessment. Certain technologies are irrelevant in this context.

KNX is indeed expensive and (technically) bad / outdated, but it is the only standard that achieves true interoperability of devices from different manufacturers. With others, there are individual manufacturer cooperations, so it can work if, for example, Philips and Ikea want it. True interoperability of current and safer technologies exists at best in DIY projects, but then you have to make it a hobby.

And now I'll take cover :oops: