As promised, I now have enough data to form a conclusion (at least for my LG front loader!). Please refer to my earlier post for the intro.
The data collected for this chart is using cold water wash. I didn’t go to the extent of measuring the wash load weight (they are always full load) but with the volume of data, you can see the average. If it’s not obvious from the chart, the average kWH per load for 800RPM is 0.109 compared to 0.143 for 1100RPM.
I know I will surely be using a lower spin speed when the weather is hot and dry like the summer we just had. Who knows, the extra water evaporated into the atmosphere on days like those might make more clouds, hence less extreme weather?