I've been thinking about generators as well, given that I've had no power for the last week. I went out to the garage and just counted up the wattage of each circuit I want to power in my breaker panel. I counted that to run everything, based on the breaker ratings which are sized for the surge current, I would need a 59kW generator. I don't want to run everything, just some circuits.
My biggest item to power is the 3 ton central AC system, which has a 50A breaker for the compressor and condensor, and draws about 1/2 (roughly 350W) hp for the air handler. Reason I want to run the central AC is beause the house got very muggy and damp during the week the power was out, and I want to keep it dry. I figure $3k for a generator to power the central AC is a whole lot less than replacing all the wallboard after it starts to grow mold. I think I can power everything I want with a 15kW continuous machine, assuming I shut off the A/C before I run the water pump. I'm looking at a Generac that runs on gasoline, and a Honda that runs on either Propane or gasoline. I like the dual fuel machine since it gives me more options to run it after a hurricane blows through, and I could chain the propane machine tho the patio in the back so nobody steals it, and not have to worry as much about noxious fumes from the exhaust so close to the house. Gas is really hard to get after a hurricane, diesel would need to be purchased in volume and it an go bad after time, but propane stores indefinately and it runs the rest of my house anyway (water heater, stove, dryer).
I'm going to wire a sub panel into the main panel, and power the main panel through a sub panel with the generator. I already have a master cutoff switch to turn off power from the meter, so that portion is done. I don't want an automatic transfer switch because I don't want the generator to run any time the power goes out, I want to manually start it whenever power goes out for significant periods of time. I also am planning on just turning off the breakers in the main panel for the outlets I don't want to run. My main concern is the central AC, water pump, some lights, the refrigrator, and maybe the microwave. However, I have a gas stove/oven so cooking really isn't an issue even with no power so the microwave is optional. As a power saving idea I'm also planning on replacing all my bulbs (lots of 60W and 100W) and installing the 13W flourescent bulbs. Doing this removes a little more than 1kW from the required generator size.
These are my preliminary thoughts as I prepare to spend about $4000 for everything. Trying to think things through before I spend the money.
