How Many Amps Does a 18,000 BTU Air Conditioner Use?

Answer
6.8 A at 240 V · 1,636 W

Running watts ≈ BTU ÷ EER. With a typical EER of 11, a 18,000 BTU unit uses about 1,636 W, which is 6.8 A at 240 V. Starting current is 2–3× higher for a moment on units without an inverter compressor.

Free, no sign-upInstant resultsUpdated October 2026
Calculate
Circuit
W
V
A
PF
1.0 for heaters and lights; 0.8–0.9 for motors.
Result
–
How we calculated this

    For estimating and educational purposes only. Results are approximate and are not a substitute for a licensed professional, the manufacturer's instructions or your local code. Disclaimer

    More questions like this

    5,000 BTU6,000 BTU8,000 BTU10,000 BTU12,000 BTU14,000 BTU24,000 BTU36,000 BTUAll quick answers

    18,000 BTU air conditioner electrical data

    Value
    Cooling capacity18,000 BTU/h (1.50 ton)
    Running power (EER 11)1,636 W
    Amps at 120 V13.6 A
    Amps at 240 V6.8 A
    Typical circuit15 A, 240 V
    Energy per 8 h13.1 kWh

    Check the nameplate: it lists the rated amps (RLA) and the maximum breaker (MOCP). Inverter mini-splits use less at partial load.

    Frequently asked questions

    Can a 18,000 BTU air conditioner run on a 15 amp circuit?

    No. It needs a 240 V circuit, typically 15 A.

    What size generator for a 18,000 BTU air conditioner?

    At least 4,500 starting watts, or less with a soft starter or inverter unit.

    Open the full calculator: Watts, Amps & Volts Calculator →