(In)Accuracy of a Kill-A-Watt for measuring low power usage

[Racer X]

michaelb wrote:
[quote=Racer X]
I have always run the Kill a Watt setup for a day or two, and divide the power consumption by the time to get average consumption.

You could easily check a freezer and read it while the compressor is running, or not.

I am also confused by the math and how this works. I don't pay attention to the instantaneous demand. I plug it in and let run for a period of time, days or weeks, and then divide by the hours. Is this saying that method is not accurate?
you are doing it right. Same method, different words.