Why are 240 volt heaters more efficient?

Answer 1

Running larger motors on 240v means they operate with lower currents (amps).

European System vs North American System Comparison:

By way of a practical example, a common 120 volt American receptacle is limited to supplying a load of approximately 1800 W (120 V at 15 A) while a British 'socket outlet' can supply a load of very nearly 3000 W (230 V at 13 A*). This means, for example, that in Britain it is common to have 3-kW kettles which boil very much faster than N American kettles - and, as we all know, a cuppa tea is terribly important to Brits!

(*Standard 230 V British socket outlets are rated at 13 A.)

Answer 2

For the same power consumption, the 240V unit draws only half the current (Amps) compared to the 120V unit. Smaller current flowing in the line cord (as well as the house wiring) means less loss in the wiring before the power ever reaches the heater. This is the main reason that commercial utility power is shipped around at high voltages, and stepped down just before it's delivered to the customer ... that way, the power company loses less of it before it can be sold.

Answer 3

Question is not clear! efficient compared to what?

anyways,

240 Volts generaly have the same effectincy as 120 Volts; however, 240V heat much faster due to the higher voltage and most likely amps avialable on the circuit feeding the heater.