After a number of Northeast storms my wife _really_ wanted a generator -- small change for some storm victims but a week without power is tough. I wanted a portable just to keep the fridge freezing. nope. (nearly) whole house. Generac, auto switch over and needed to upgrade our LP system to 1000gal. tank. (excavation, permit, burying the line, besides teh unit expense) I say nearly because we can use the A/C -- but not the ovens or dryer at the same time. A small compromise.
Our Town Hall put in Kohler gens. I've had no probs with the generac. I change the oil myself but now its in need of a periodic tune-up. Its a small engine tune-up. Somehow, I get the feeling it'll be 400$. I can get a Porsche tune-up for that. In 3 or 4 years its been called upon for maybe a total of 10 hours. like the other posters say: professional install, stay on top of the maintenance. And it is a bit of a gouge business -- but what in Electrician Land isn't? Like Don Henley says: How bad do you want it? I shopped around and probably saved 1-1.5K. I did the tank slab and line excavation myself and probably saved ~500$ (lot of rock (rented a mini-mite) and a 30' long, min 2' deep trench) Overall spent about 12 or 13K. But its a selling point for the house...
My only real gripe was within one year the battery died, installer said Generac doesn't warrant the battery, neither does the installer. Really? what the flatulence? They replaced to the tune of about $250 installed. the tech was nice enough to give me the specs on the battery so I can diy if it happens again.
Know b4 you buy: your neighbor/friend who gets 20 days on a tank. Take a look at the consumption rating for whatever unit you're considering. My unit burns a min. of 2.35gal/hr and a max of 2.6 or 7. Do the math and it ain't 20 days - on a full tank. we use the tank for some hot water and cooking and weekly exercise (yup, every Wed at 2pm)-- that's about 50-75g/yr. Then keep in mind once you lose power and your tank runs low -- will a LP delivery truck make it into your driveway? Yeah, NG through utility pipes is a sigificant, on-going, advantage -- unless they're damaged in the cataclysm.
My idea to stretch a tankfull and save some $ and CO2 is that I (will) turn the unit off overnight. the house is tightenough to stay cool or warm and the fridge will have no probelm for 6-10 hours.