The choice of metal in a tea kettle is largely a matter of opinion, but people wanting a classic look in their kitchen and a status symbol choose copper tea kettles. Boiling water in a copper kettle is quite efficient, as copper conducts and transfers heat very easily.
Because of the efficient heat transfer, copper heat kettles take less time to boil water and cost less in terms of energy. Because they have to spend less time over high heat, they experience less wear and tear over time, making replacement less frequent. Stainless steel is another popular option with efficient heat transfer, but copper gives the kitchen a distinctive, dignified look.