In the U.S. there is also the difference in current in each leg between L1 and L2. With Techtoniq, the difference is very apparent, and seldom do I see anything exactly a 50-50 split.
Nevertheless, what you say is quite true regarding non-unity power factor, which is a variable, EnviR cannot address based on simply current only measurements.
Maybe it was just a coincidence, but the other day I did a side by side comparison of my EnviR Energy Now vs. Utility Meter, and when my whole house consumption was almost exactly 1000 watts, they were almost exactly the same measurements. The difference was less than +/-1%, which was quite satisfying while it lasted. At much lower whole house consumption, the EnviR readout was much higher than the utility meter, and vice versa at much higher levels of several kW; apparently a totally non-linear relationship.
What might be a better way to "adjust" for inaccuracies in your product, is for the user to accumulate sufficient data in the EnviR to obtain a measurement of "average" kWh per day (over consecutive 24 hour periods), say for a one month period, or longer. Then, look at the utility bill over the same period of time and calculate the household's average consumption rate per day (if not already given on the statement). The difference between the two averages, as a percentage of the utility meter taken to be the "actual", could then be used to (software) adjust the Envir's realtime Energy Now reading. This would provide a simple way to "calibrate" (albeit crudely) the EnviR display monitor. Of course, the caveat that must still be understood, is the display still reports an approximation of the actual power consumption at any given moment.
I think this method would be more efffective for correlation purposes in terms of COST assessments, which is what most EnviR users are most increased in using it for in the real world.
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