Starting watts vs running watts
Running watts is the power a generator sustains continuously; starting watts is the extra surge it can supply for a few seconds while a motor spins up. Size a generator so running loads fit the running rating and the single largest motor start fits within the starting rating.
Motors — refrigerator compressors, well pumps, air conditioners, sump pumps — draw two to six times their running power for the moment it takes to reach speed. Resistive loads like heaters, lights, and electronics have no meaningful surge.
The practical sizing method: add up the running watts of everything that will run at once, then add the largest single starting surge (starting minus running for that one appliance) — motors rarely all start in the same instant. Manufacturers commonly name models by starting watts, so a “9500-watt” generator may sustain only 7,500 W.