A single 2000w generator is marginal.
- First that's a peak output rating not continuous. Continuous is typically around 1600w.
To run an air/con you need to consider both the startup power and continuous power demand. Continous for a typical air/con unit is going to be around 9-12 amps (or 1200-1400w). Sounds good that is below 1600w rating but to get the compressor turning, you need a surge of extra power...typically 2-3 times as high...that's way beyond what a 2000w generator can do.
There is a partial solution. They can add a "soft start" unit to the air/con. This is basically a small capacitor that stores up some power and when the compressor kicks on, the capacitor dumps it's power into the system and makes up much of the difference...2000w is still marginal.
As mentioned by others, traditional generators have to run at constant speed so that the hertz stays correct. High speed operation tends to be noisy. Inverters take DC power and electronically invert it to create AC power. This allows the motor to be throttled to match the demand. This allows the generator to be more efficient and to be quieter.
There is a catch with the quieter. If you are running the air/con, the generator is going to throttle up for the higher load. Under light loads, the generator may just be a soft hum but when putting out full power, it's not nearly as quiet.
2000w generators are popular because they are easy to carry around. To mitigate the limitation, some manufacturers have designed them so you can link 2 together (Don't try to DIY connect two generators, its more complicated than it sounds and you can cause a lot of damage). Of course, this is an expensive solution.
We have a 2400w Yamaha that does fine for a single air/con (plus a few minor loads). It's probably at the low end of what I would consider. If I was buying a new one, I would probably bump up to 3000w.
