Need help with Kill-A-Watt meter

For your task you don't need all of these:

Just read the Watts.

w.

If that's all you want to know, spiffy, ignore the rest.

----- No, really, "Ethel, don't look..."

----- "...but it was too late. She'd already been zowwed."

Volts is pretty much "is power service OK." Hardly ever needed, though it might help you check that a portable generator was in range if you were using one. Quite rare for it to be out of range if you have power at all.

You forgot Hz, which is frequency, again, mostly useful for checking a generator. If the power frequency provided to your house by a major utility is actually off, go buy a lottery ticket. If the KAW readout says it's off by a little, it's the KAW's low tolerances 99.9999% of the time.

VoltAmps are volts times amps, and how different that is from watts is power factor. For the home user (and KAW is a home-user oriented device) it's primarily of use to figure out what-size UPS you should buy for your computer and/or network hardware. A 100W device with a 200VA (0.50 power factor) will need at least a 200VA rated UPS to run it.

Larger power customers actually have incentive to improve power factor (closer to 1.00 is better) in the form of lower costs. Home users typically get a free ride. If you have a generator or UPS, improving your power factor will be in your self interest for the items you run from those power sources.

If you haven't already noticed - the main reason you want to pay attention to the KAW clock is that the KAW resets on the briefest of power interruptions. So if you leave it for two weeks, make sure it counted for two weeks. It would be nice if it would hold time for a minute or so, but it doesn't.

After the initial surge of checking everything, it may get more sporadic use, but it is nice to have. Most recently used mine to see what a new computer build was actually using as it ran. When I had it plugged into my desktop, I could tell when newswatcher hung on exit, as the power use would rise. Of course, after a few seconds of that the fan noise increases, and if you've grown to expect the occasional hang-on-close you look for it, but it was amusing to note.

It does make me yearn for a 240V version from time to time. I actually put a Murata readout (does not total KWH, but provides volts/amps/watts and PF) on my well-pump for monitoring. I can roughly equate the water depth to the amps/watts, and hope to be able to spot signs that the pump is going bad before it actually dies (though I also plan to put a new pump on the shelf after 5-7 years or so, in order not to be panicked into buying one in a hurry at high cost.)