"Rob Horton" wrote in message
...

Thinking along the lines if efficiency, the amount of energy needed to
boil water depends on the temperature differential between the starting
temperature and finishing temperature. Maybe keep several litres of water
on a sunny windowsill to warm up before using. Also, not all beverages
need boiling water. Monitoring the temperature of the water in the kettle
and then turning it off when the desired temperature has been reached
would be a good idea.

Lidl did a nice plastic 3kw kettle with an additional stat for hot water
rather than boiling for £9.99.
It works OK but you have to remember to switch it off if you are using the
stat or it will keep it hot until you do.