A few comments:
I've been thinking about a standby unit myself.
Costco has Kohler 12KW units on sale now thru Sept. 17 for $2250--plus you find electrician and LPG guys to install, estimated to run around $1,000. Regular price at Costco is $2,500. Comes with a transfer switch, runs on propane or natural gas.
I have a 6KW portable unit with electric start and a transfer switch. It has worked OK, but power only fails when the weather is miserable, blowing rain or snow. Noisy. Once lost power for several days, ran out of gas. Went to town for gas; could only get the ethanol contaminated stuff. Filled up the generator, fired it up and the line power came back on within 30 seconds. Grumble, grumble.
Question for anyone who knows: Starting load of the 1/2 hp well pump is somewhere around 3.5+ KW, so I am told. If the refrigerator, freezer, furnace fan, etc. and lights are on, it looks like we come close to overloading the unit when the well comes on. And we want to wire in the microwave, but haven't done that yet. The well pump is old and the well guy really wants us to replace it with 3/4 hp when the existing pump dies. At that point, I know we'll overload the generator when the well fires up.
So, how important is the surge load? There is no surge load rating on the generator, just the 6KW rating.
Gas concern: Install a shut off valve in the fuel line and shut the generator down by shutting off the gas to avoid varnish buildup in the carb. And in many states you can get ethanol free gas for off road use--check with marinas. Ethanol separates out in storage and absorbs water, 2 things you don't want to happen to your fuel.
Do you really need A/C when the power goes out? I can understand that in Florida when tropical storms come thru with high humidity, but what about places like Connecticut?