Which is more efficient in wall heaters, 120 or 240?

Voltage is irrelevant to the efficiency of electric heat. Higher voltage relates to lower amperes and savings on copper wire and installation costs.

If you have a 5000 watt heater that can be connected with either 120 or 240 volts,at 120 volts the heater will draw 42 amps, at 240 it will draw 21 amps.

The heater still gives the 5000 watts of heat, but at 240 volts , you can use smaller wire.


The efficiency of electric heat is realized by having the proper amount of insulation, efficient windows, eliminate drafts, and something I think is important for electric heat, is to be sure there is a humidifier to add moisture to the heated air.

I hope this helps, any other questions get back with them.