The indoor module only works together with the weather station. The room air sensor runs alone (connection via WLAN).

Hello
As far as I can tell, the room air sensor is plugged in, the module has a battery, and can be placed anywhere. The module also has less data (no noise and CO2). I have several sets, but always the 'meteo set'. The module can also be placed in a room. The base (220V) can be supplemented with wind and rain sensors. Everything has been working very well for 3 years.