Best retrofit smart home new build

So normally, when building, the FHB is also equipped with valves. I don't know of a construction site where there are no room thermostats or valves. Slow or not. Regardless of whether it is residential buildings or single-family houses.

If you build with KFW, individual room control is even mandatory as far as I know.

The question I asked myself was whether one should make this smart, or if it is nonsense.

Everything beyond a temperature display to satisfy curiosity or to use this information in other ways (e.g. statistics) is rather unnecessary in modern and inhabited houses.

The underfloor heating simply cannot react as quickly as you want (or as you know from high-temperature systems aka radiators). By the time the screed has warmed up or cooled down, the next morning has already dawned. Or even 2-3 days have passed in particularly efficient systems.

You can still install an ERR if it’s required there. But in the end hardly anyone uses it because it’s unnecessary for underfloor heating. Sure, with systems that are completely botched, it’s a different matter. Then it only works via the emergency brakes on the walls.

Quick side question, what exactly is meant by ERR?

Single room control means one thermostat in each room and a valve on each circuit.