[eldaisfish]

>It is not obvious at all and requires calculations.

Heating water in a domestic setting on a gas stove is incredibly inefficient and you don't even need a calculator to know why - put your hand adjacent to the stove and feel the heat being lost. This is not a small fraction, it is significant unless you run the stove really low and spread that heat over a large area.

Now put your hand and any point outside an electric kettle and see how much heat you can feel. Almost none.

This isn't really as complicated as you're making it out to be.

[citrin_ru]

Thermal loss of course bigger for kettle on a gas stove than for an electric kettle. But while electricity is generated on a gas/coal powered plan a lot of heat emitted into the environment, and we cannot ignore this if we are interested in overall efficiency.