Many folks say a 2000 watt Inverter type generator (And I do recommend inverter types) won't start a 15000 BTU Rooftop AC.. Some Get lucky
3000..Should but still might not
4000 generally does (That's a pair of 2000 in parallel)
Some companies are making like 2400 or 2600.. Often they do it.
Why an inverter generator.> Two answers
CLEAN POWER.. Inverter generators have a output that is pure as a flute.
(nice clean sine wave) Some of the "Contractor" Types... Well you look at them with a proper scope you feel the need to change underwear they are that scary.
That spike filled waveform is hard on your Electronics.. Does not bother light bulbs much. and most motors can take it. But radios, televisions. YOUR CONVERTER... Not going to be happy
There are some that are not so bad but it's been long enough since I knew which were which that the report needs to be redone.
Source American Radio Relay League ARRL.ORG but the article is likely behind a membership wall.
Alas the search engine did not find the article.. I may have it archived locally But again my computer did not find it. and I've 10 years of archives to search.