What are the advantages of heating water in a kettle?

The advantage of heating water in a kettle is less thermal energy passes from the walls and the lid of the kettle, into the air. This is because kettles are made of plastic; a less successful heat conductor than metal; making water have lower thermal conductivity, therefore kettles are more efficient for heating water than pans which are usually made from metal; an efficient heat conductor, that enables heat to pass through the pan's sides and lid, and into the air.