First. out of courtesy to you and your neighbors I will suggest an INVERTER type generator. such as the Honda EU-#000i line, not the lower case "I" at the end.. Yahama also uses this to designate inverter generators.
Second, Honda is the standard, Yamaha is the alternative, There are other cheaper Chinese brands but I would prefer not to mention them let alone own one. You pay a bit more for Honda or Yamaha, but you can find Honda Service most anywhere and Yamaha is only slightly harder to find.
One A/C may run on 2000 watts (2400 in Yamaha) or may not, depending on the size of the A/C and how hot it is and a few other things.. Do not forget the load of the battery charger/converter when you calc this out, Mine draw about 1,000 watts.. EACH when they first start up with low batteries (I have 2) A 3,000 watt (3600 in Yamaha) will usually do it
Best option would be a Honda EU2000i in my book,, There are two ways to address the issue if it's not enough
1: A 2nd EU2000i and a parallel kit, OF all the inverter generators out there HONDAs are designed to work in tandem providing up to 4000 watts surge, that is MORE than 30 amps.
The 2nd is a box they make, I think I have a link to it, contains a inverter/converter and a battery.. IF your A/C is running, the house batteries are full, and you are only using say 1,000 watts, this unit will charge it's internal battery.....
If the batteries are low, and the A/C kicks in and you need 3,000 watts,,, It will switch to inverter mode, parallel with the Honda, and provide the additional power. to "Boost" the honda up to what's needed,,,, Very nice box
Will work with other generators too since it's got the magic parallel circuit in it.
Home is where I park it!