This kettle works well and would save energy and money provided you only boil the water you need and use the temperature controls when appropriate.

To achieve any savings it is vital that the kettle is switched off at the wall when not being used as it appears to use around 7W on standby - it's unusual for kettles to have a standby power consumption, but this one does. If you leave it switched on at the wall it will waste more than 60 kWh of electricity each year - not a huge amount, but enough to wipe out potential energy savings.