We got 2 AC's and wish we had 3 here in Texas. You can only run 2 @ a time BUT the 2 are typically setup front (Mstr BR) & rear (TH garage). In mine hooked together in a circular vent system. Here is the issue for us: TX is very hot and humid most of the year so need AC. I would like a 3rd unit in the center living area as we would run front & center unit most of the time cooling the living space. IF we had guests we would use front & rear at night so each bedroom was comfy. Problem is adding a 3rd isn't an option due to the current vent system, even thou was told "not a problem to add it".
Our OEM Onan can handle the load but @ best it burns .9 gallons an hour so you will need fuel frequently if your running everything all day. Best on shore power. Wish the manufactures offered a std genny option for say a Honda. Not aware they do.
Fuzion is now pre wiring its TH's for 3 AC given the demand that had been high to add one. IMHO.