You will also likely need a larger capacity gas meter. Get a plumber to spec out the size of the gas line to the generator.

Things to think about:

• Inverter generators generally use less fuel, especially if you aren't running at near full capacity.
• Many inverter generators can be paralleled together to double their capacity when needed.
• Get a 240V generator if you plan on connecting it to your house wiring.
• The least expensive safe and legal way to connect to house wiring is with a power inlet and an interlock on the main breaker box. Use 10ga wire for 30A, 8ga wire for 40A, and 6ga wire for 50A. An electrical permit is generally required.
• If you are going to be running it for an extended time, you don't want to be running it at full capacity. It will last longer running at 50% than at 90%.
• A MicroAir EasyStart on your AC will help with the startup surge. Very simple install, no electrical permit required. If your AC has a Locked Rotor Amperage of, for instance, 40A the EasyStart can bring it down at least 50%, allowing a 5000w (~20A) generator to run your AC.
• If you have Natural Gas available, it will be much less expensive than Gas, Diesel or Propane. NG will also be more available during the aftermath of a natural disaster. NG will give you about 65% of the power of gasoline, so a 30A generator will give you about 20A on NG.
• Many gasoline or dual fuel generators can be modified with a "snorkel" adapter for propane or NG use. There are kits for dual fuel or tri fuel. Replacement carburetors for dual fuel can often be found on ebay and amazon.
• Open frame generators are louder than closed frame, but are lighter and cheaper.
• Closed frame generators run hotter then open frame, but are much quieter.
• Portable generators generally don't have an oil filter. Get a magnetic dipstick and drain plug for those, especially if new. Metal shavings in brand new gensets is a killer.
• Generators damaging electronics is largely an exaggeration. The surge, spike, sag or other nastiness takes place when a standard generator shuts off. Turn off the generator breaker before starting or shutting down the engine. Throwing the generator breaker prevents that from getting to your electronics. It is a good idea, even with inverter generators.
• Don't use generators to run electric heat. A diesel parking heater or propane heater is much more efficient. Fuel heaters or even wood stoves are more efficient sources of heat than electric from a generator.
• Carbon Monoxide from generators kills about 70 people each year in the US. Don't operate a generator in the house, garage or any connected structure.