What size generator to run an RV air conditioner?
RV air conditioner (13.5k BTU) draws about 1,400W while running and surges to 3,000W on startup. Allowing 20% headroom, size for at least 3,600W of starting capacity.
The reason 2,000W inverter generators are often not enough for an RV. Two paralleled 2,000W units is the standard fix.
The surge is the number that matters. A generator rated to 1,400W will stall the moment the motor kicks in, because for a fraction of a second it needs 3,000W. Manufacturers advertise running watts, which is why people routinely buy one size too small.
Units that cover it
- Predator 4200 Watt Dual-Fuel Super Quiet Inverter
4,200W starting · 40% headroom · $799.99
Comfortable headroom without overpaying for capacity, has a CO shutoff sensor, runs at 59.8 dB, runs on propane as well as gasoline.
Check price - Predator 3500 Watt Super Quiet Inverter
3,500W starting · 17% headroom · $799.99
Sized close to your load with a little room to spare, has a CO shutoff sensor, runs at 56 dB.
Check price - WEN 56450iX
4,500W starting · 50% headroom · $829.49
Comfortable headroom without overpaying for capacity, has a CO shutoff sensor, runs at 58 dB.
Check price
Running more than one thing
Most people are not powering one appliance. Add everything you need at once and the calculator works out the real peak — your total running load plus the single largest surge, not the sum of every surge.
Size the whole load