How Many Amps Does a Space Heater Use?

A space heater uses about 12.5 running amps at 120 volts (roughly 1,500 watts). To get your unit's exact draw, divide the nameplate watts by 120: amps = watts / volts. A 1,500 watt space heater draws exactly 12.5 amps. As a fixed continuous load on a dedicated circuit it is sized at 125% (12.5 x 1.25 = 15.6A, NEC 424.4(B)), which exceeds a 15A breaker, so it needs a 20A circuit. A portable heater can instead plug into an existing 15A receptacle, where its 12.5A is 83% of the circuit, so it should be the only significant load and never on an extension cord. Two 1,500W heaters cannot share one 15A or 20A circuit.

A space heater belongs on a dedicated 20A / 120V circuit (NEC 210.23(B), 424.4(B)). At 12.5 running amps it stays within the 80% continuous limit of that breaker. Do not put it on a shared circuit with other large loads.

Divide the wattage on the nameplate by the voltage: amps = watts / volts. A space heater at about 1,500 watts on 120V works out to 1,500 / 120 = 12.5 amps. The nameplate always governs over a typical value.

Same answer: electric space heater is another name for a space heater. It draws about 12.5 amps at 120V on a dedicated 20A circuit. A 1,500 watt space heater draws exactly 12.5 amps. As a fixed continuous load on a dedicated circuit it is sized at 125% (12.5 x 1.25 = 15.6A, NEC 424.4(B)), which exceeds a 15A breaker, so it needs a 20A circuit. A portable heater can instead plug into an existing 15A receptacle, where its 12.5A is 83% of the circuit, so it should be the only significant load and never on an extension cord. Two 1,500W heaters cannot share one 15A or 20A circuit.