Electrical power is a physical quantity that is expressed as electrical work over time. It is denoted P, its unit of measurement is watt [W].
In AC circuits, one needs to distinguish active power, reactive power and apparent power (and sometimes complex power).
P = U * I * Cos(Phi)
In the context of NETIO products
NETIO smart sockets measure the active power [W] as a single RMS value for each measured channel separately.
To calculate the immediate power, NETIO uses the True Power Factor value; unlike cos(Phi), TPF also accounts for the actual waveform.
P [W] = U [V] * I [A] * TruePF [-]
The measured power value, as displayed by the NETIO device, accounts for the actual waveform (load type).
For instance, PowerPDU 4C has 4 output electrical sockets and measures 4x electrical power per socket + one overall value (for the whole device).