An electric kettle usually takes less electricity than heating a stove kettle on an electric hob. The reason is simple: an electric kettle has a built-in heating element close to the water, so more heat goes directly into boiling. A stove kettle needs electricity to heat the hob first, then the hob heats the kettle base, and finally the kettle heats the water. More heat is lost through the surface, surrounding air, and cookware contact.