What is the difference between rue power (watts) and apparent power (VA)?
Apparent power is the product of RMS voltage and RMS current. True (or active) power is a time average of the instantaneous power (product of instantaneous voltage and current). For resistive loads the true power and the apparent power will be the same. Inductive loads, such as motors, have a phase shift between the voltage and the current waveforms. This phase shift results in a lower true power measurement than if the voltage and current were in phase. As a result, motors will have higher apparent power than true power. The WattNode measures true power and so for some loads will report a lower power than would be estimated using an ammeter and a voltmeter to compute the apparent power.
