Also, I went to the Kill-A-Watt web site. It looks like you can't measure
any appliance running at 220 volts, correct?

I have a wall A/C unit in my apartment that plugs into a 220 outlet. I
read somewhere that even a fairly small one of these units uses 3500
watts. I imagine that the 3500 is only when the A/C is running the
compressor. So the average wattage would depend greatly on the outside
temperature, I would think.


I have the UK version which is not even branded, but looking at it, it's
obviously internally identical to the Kill-A-Watt. It's designed for 240V
but works fine all the way down to 60V so I suspect the 120V model will work
on 240V but have not opened one up to compare. At any rate the power supply
is a simple capacitor and zener arrangement so it would be easy enough to
modify with a lower value capacitor if the zener heats up too much on 240.
If in doubt, it shouldn't be too hard to get the UK model and build some
plug adapters as I did, back before it was widely available in the US.

I used mine to measure the draw of my 3 ton (36,000 BTU) central AC and
found that the outdoor unit draws about 3500W with a power factor of 0.91.
You're correct that current draw varies with head pressure which varies with
outdoor ambient temperature. I doubt your window AC is bigger than 1 ton, so
even with the indoor fan, I'd be shocked to see it drawing more than 2KW and
really it's probably closer to 1200W.