I doubt it makes much impact, boiling a kettle is resistive heating, so the majority of the energy goes into the liquid (and a little into the kettle itself). Most of the loss will be to steam each time you boil (getting a fancy kettle that warms to 95 degrees is probably smarter). I think someone calculated the actual costs of boiling a kettle and it wasn't really much.
Plus he's a Radio DJ, so can probably afford to boil a kettle.