How Many Amps Does a Box Fan Use?

A box fan uses about 0.8 running amps at 120 volts (roughly 100 watts). To get your unit's exact draw, divide the nameplate watts by 120: amps = watts / volts. A box fan draws well under 1 amp (about 50-100 watts on high) and shares any 15A or 20A circuit with room to spare. Even a dozen fans stay within one circuit; the running load is tiny. Check the label for the exact watts if you are sizing a generator or a long extension run.

A box fan does not need its own breaker; at 0.8 amps it shares a standard 15A or 20A / 120V circuit (NEC 210.23(A)). Just avoid running it at the same moment as another heavy load on the same circuit. Keep the total continuous load under 80% of the breaker.

Divide the wattage on the nameplate by the voltage: amps = watts / volts. A box fan at about 100 watts on 120V works out to 100 / 120 = 0.8 amps. The nameplate always governs over a typical value.

Same answer: window fan is another name for a box fan. It draws about 0.8 amps at 120V on a shared 15A or 20A circuit. A box fan draws well under 1 amp (about 50-100 watts on high) and shares any 15A or 20A circuit with room to spare. Even a dozen fans stay within one circuit; the running load is tiny. Check the label for the exact watts if you are sizing a generator or a long extension run.