Lots of good info. Let me try to make it short and sweet.
- If you MUST run your whole house A/C or heat pump, you need a permanently install generator
- If you MUST run 240V appliances (electric stove, electric water heater, electric clothes dryer) or have a well pump you will need at least a 5000W generator
- If you do NOT have any of the above, you can get by with one 3000W generator, INCLUDING running one windows air conditioner !
Oversized generators are a waste of money TWICE. Once when you buy and every time you fill the tank. I would not waste my time looking at anything except and inverter generator.
I strongly recommend that you have a professional electrician install a
generator interlock in your main breaker panel and a 30A power inlet on the outside of you house, close to where you will run your generator.