It would be interesting to test. quick, someone poke Technology Connections.

afaik electric kettles are the most efficient machines around. something like 95% efficiency

Right. The hob needs to heat up entire surface of your cookware, and kettle transfers heat directly from the element below to water - only then some of that heat is dissipated.

If you have both, and a timer on your phone, should be easy enough to check. Put the same measured amount of water in both and see how long it takes to boil.

Right. The hob need to heat up entire surface of your cookware, and kettle transfers heat directly from the element below to water - only then some of that heat is dissipated.