The neoHub is the network coordinator. It communicates with the mains powered Neo Devices via a mesh network. This mesh network is designed to relay the signals between devices, so the total communication distance is greater than a standard RF System.
The neoAir can join the mesh network but does not relay signals, so in a system made up of only neoAir you may require more neoPlug/Repeaters to extend the communication range. The neoAir also communicates directly via RF to the receiver and so in both systems the neoHub is not required for the heating to operate.