Appliance Amperage

How Many Amps Does a Window Air Conditioner Use?

The running amps a window air conditioner draws, the watts-to-amps math behind it, and the branch circuit it belongs on.

Quick answer: A window air conditioner uses about 10 amps at 120V (roughly 1,200 watts). The motor briefly surges higher at startup. It belongs on a dedicated 20A / 120V circuit. Amps = watts ÷ volts; the nameplate governs.

Window Air Conditioner Amps by Size

Typical running watts and amps for a window air conditioner by size
Window Air ConditionerTypical WattsVoltsRunning Amps
5,000 BTU450 W120V3.8 A
8,000 BTU800 W120V6.7 A
10,000 BTU1,050 W120V8.8 A
12,000 BTU1,300 W120V10.8 A

Representative running values, not code data; the nameplate always governs. Motor loads also draw a brief startup surge above the running amps.

Window Air Conditioner Circuit

Typical draw and circuit for a window air conditioner (NEC 440.62, 210.23(A))
Typical watts1,200 W
Voltage120V
Running amps10 A
Startup surgeYes (motor)
Circuit20A dedicated

A window air conditioner draws about 4-13 amps depending on size: a 5,000 BTU unit is roughly 4 amps, a 12,000 BTU unit near 11-13 amps, plus a brief compressor surge. Small units share a 15A or 20A circuit; a large 120V unit wants a dedicated 20A circuit, and the biggest models are 240V. The unit's plug type tells you which. Amps = watts / volts; keep the continuous load under 80% of the breaker. The nameplate lists the exact draw and always governs over a typical value.


Compute Your Unit's Exact Amps

Read the watts off the nameplate and enter them below to get the exact running amps at 120V or 240V, with power factor for motor loads.


Frequently Asked Questions

How many amps does a window air conditioner use?

A window air conditioner uses about 10 running amps at 120 volts (roughly 1,200 watts). Because it is a motor load, it surges to several times that for a moment at startup. To get your unit's exact draw, divide the nameplate watts by 120: amps = watts / volts. A window air conditioner draws about 4-13 amps depending on size: a 5,000 BTU unit is roughly 4 amps, a 12,000 BTU unit near 11-13 amps, plus a brief compressor surge. Small units share a 15A or 20A circuit; a large 120V unit wants a dedicated 20A circuit, and the biggest models are 240V. The unit's plug type tells you which.

What size breaker for a window air conditioner?

A window air conditioner belongs on a dedicated 20A / 120V circuit (NEC 440.62, 210.23(A)). At 10 running amps it stays under the 80% continuous limit of that breaker, with headroom for the startup surge. Do not put it on a shared circuit with other large loads.

How do I calculate the amps a window air conditioner draws?

Divide the wattage on the nameplate by the voltage: amps = watts / volts. A window air conditioner at about 1,200 watts on 120V works out to 1,200 / 120 = 10 amps. Add a startup surge of several times that for a fraction of a second on the motor. The nameplate always governs over a typical value.

Does the size of a window air conditioner change the amps?

Yes. A 5,000 BTU draws about 3.8 amps, while a 12,000 BTU draws about 10.8 amps. See the table above for the range. The rating on the nameplate is the number to size the circuit to.

How many amps does a window ac use?

Same answer: window ac is another name for a window air conditioner. It draws about 10 amps at 120V on a dedicated 20A circuit. A window air conditioner draws about 4-13 amps depending on size: a 5,000 BTU unit is roughly 4 amps, a 12,000 BTU unit near 11-13 amps, plus a brief compressor surge. Small units share a 15A or 20A circuit; a large 120V unit wants a dedicated 20A circuit, and the biggest models are 240V. The unit's plug type tells you which.


How Many Amps Do Other Appliances Use?