My kettle boils a mug's worth of water in less than a minute, and it takes me longer than that for even a brief toilet visit and washing of hands. I have learned not to switch the kettle on until I get back from the bathroom, otherwise I'll be boiling the water twice.

Important factors: 1) Britain has 230V mains power so electric kettles can boil water incredibly quickly, 2) The stereotype about Brits and tea is true in my case. I get through three to six mugs of the stuff per day. 3) Hot tea must be made with boiling water. Power isn't cheap and re-boiling the water adds up over time.

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.