STANDBY GENERATORS

NRALIFR wrote:
These were my decision points when considering a standby generator:

First of all, what size do I need? There are basically two ways to go here: critical circuits, or everything. There can be a huge difference in KW size (and therefore, price) when comparing the two, especially if "everything" includes one or two central AC's, one or two electric water heaters, electric cloths dryer, electric stove and oven, etc. If you need everything working in your house when the power goes out your going to have to add up all those loads, and size the generator accordingly for the max load.

In my case, I went the critical circuits route. Critical to me doesn't include air conditioning. Our water heaters, stove top, and clothes dryer are NG, so I'm able to cover more 110v circuits by not covering any of the 220v circuits with the ATS. During a long power outage I want to be able to prepare meals, stay warm, get ready for work, keep the fridge/freezers running, operate the garage doors, and have a reasonable amount of lights working. A 10KW covers all that at my house easily. By far, most of the power outages around here are during the time of the year when AC just isn't needed. If we ever have a long outage during the summer, I'll just go buy a portable 110v AC and use it to keep our bedroom comfortable.

Fuel source: I wouldn't even consider a liquid fuel source for a standby generator. The added concerns of keeping the fuel source clean and fresh rules them out for me. Depending on where you are, your covenants or deed restrictions my prohibit keeping large liquid fuel storage containers around as well. I'm using NG to fuel mine since it's already available. Our area isn't prone to earthquakes strong enough to disrupt the supply, so I don't worry about that. But even if were, any generator that can run on NG can also run on propane. Mine makes it easy to switch between the two fuels by just flipping a lever. So, if the NG supply was disrupted around here, it would be possible to switch to propane if needed.

Another consideration with the various fuel sources is the effect is has on the rated output. A tri-fuel (gasoline/LP/NG) engine will only sustain rated output when running on gasoline. Propane will de-rate it's output some, and NG will de-rate it even more. My dual-fuel (LP/NG) 10KW is actually a 9KW while running on NG.

Another consideration with using NG: Can your meter supply enough NG to keep your generator running when all of the other NG appliances in your house are running at the same time? In my case, that means two furnaces, two water heaters, four stove-top burners and the clothes dryer all on while the generator is under max load. My local NG supplier had to install a higher-flowing residential meter at my house in order to supply the volume needed. They didn't charge me for swapping the meter.

Air or water cooled: By far, most of the home standby generators are going to be driven by air-cooled engines. Extreme heat will also de-rate an air-cooled generator's sustained output. If you want your generator to provide enough power to run your air conditioners on the hottest summer days (around here that can mean 100+ degrees) while also supplying all your other electrical needs, you need to over-size it so it doesn't get too hot and shut itself down. Or, spend the extra $$'s up front and get a water cooled unit.

Manual or automatic: There are a lot factors that will play into this, and $$$ is just one of them. Where your main CB panel or your main power input is located on your house is going to affect how easily an ATS can be wired in. If your ATS includes CB's for individual circuits, your going to need access to the main CB panel. When I installed my generator, I was already remodeling a bedroom that the main CB panel was installed in. I had the sheetrock off all the walls, so it was easy to install the ATS panel next to the main CB panel, and run all the wires outside where the generator sits.

We've had ours for 7-8 years now, and (knock on wood) it's been reliable so far. We've had several short outages in that time, and a couple of pretty long ones. I think it's run as long as five days straight. That added about $100 to our NG bill for that month, and I had to do an extra oil change on the generator that year.

Those are just my experiences, and I hope it helps you in deciding which way to go.

:):)

Excellent post! Very much my same decision-thought-process that led me to my (about the same as your) decision.

I just hadn't had enough coffee to type so much when I replied earlier.

:)

Only thing I'll add to the idea or option of electing NOT to place either of my central A/Cs on a protected circuit...

If I do happen to have an extended outage where A/C is necessary I have two options.

1) I could move the (smaller) upstairs a/c from a non-protected circuit to a protected circuit.

2) park the RV in my driveway and plug it in to one of the already protected circuits and run it's A/C