I use an electric kettle but remember that in the US outlets are 120V, so they take a lot longer to heat water than in countries with 240.
So the microwave isn’t much less efficient than the electric kettle, mainly because some of the energy is heating the mug/container. The least efficient is a stovetop kettle on an electric stove.
But I’m curious, why are Europeans so horrified by the idea of heating water in the microwave? Is it related to power consumption, or is there some other reason?
Oh, now I see! You don’t understand that a microwave can boil water, you think it can only warm it up a little. Thank you for clearing up my confusion.
Whenever I hear Europeans accuse Americans of being arrogant, I can only laugh. Feeling superior about something like how you boil water is hilarious.