Start-up surge is the trap on every source
A standard window AC draws about three times its running watts for the first second the compressor starts. That trip happens on a generator, a 20A house circuit, or a festival pedestal. Inverter ACs (soft start) are much easier on all three.
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Soft-start kit or inverter window AC
Cuts surge on house, pedestal, and generator alike.
Which source
- House / shop. A shed or indoor cooler. Put the AC on its own 20A circuit. Cost is kWh on the bill.
- Event pedestal. Trailer at a fair or campground. Check amps before you worry about fuel.
- Generator. No pedestal, or you are away from the building. Size for surge, then fuel.
- Solar. Off-grid farm box, or a trailer that sits. Battery covers night (and extra cloudy days if you ask). Array covers the day's kWh. The inverter has to start the compressor — that is usually the expensive part, not the panels.
Assumptions
Continuous circuit ratings use 80% of breaker amps (NEC). Generator fuel is a typical inverter curve (about 0.07 gal/h idle plus 0.11 gal/h per kW for gasoline; propane about 1.4× that volume). Solar: battery kWh = (average watts × hours on battery × cloudy days) ÷ usable fraction (80% lithium, 50% lead-acid). Array watts = daily kWh ÷ peak sun hours ÷ 0.70 (dirt, heat, angle). Charge-controller amps = array watts ÷ battery voltage ÷ 0.8. Inverter continuous is running watts + 25%; surge is the compressor start. Parts cost is panels and battery only. Not an electrical design.