Choosing the Right Generator

Protect yourself from electrical outages and you’ll no longer be powerless.

| January/February 2009

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Most of us live just one blackout away from the Stone Age, but this fact is easy to forget until the lights go out. A good electric generator makes your home blackout proof. It’s relatively inexpensive insurance against complete loss of household power. Plus, portable units are convenient when you need electricity beyond the reach of an extension cord.

All generators combine an internal combustion engine with electrical components to create electricity for powering appliances and tools. Choosing a generator involves several key decisions. How much power do you really need? How often do you expect to use it? Will it be for emergency household backup? For tools? Both? What level of quality makes sense? What kind of fuel? How will you get the power from the generator to items in your home?

More power to you

The first thing to consider is generator output - determining the size that is right for your situation. This sounds simpler than it really is because not all items on your wish list are going to be used all the time or at the same time. Also, some appliances (such as furnace fans, sump pumps, washing machines and refrigerators) require more start-up power than their specified ratings.

Generator output is measured in watts, a unit of power derived by multiplying electrical flow rate (amps) by electrical pressure (volts). One typical household outlet, for example, delivers a maximum of 1,800 watts (15 amps multiplied by 120 volts), or the equivalent of a small portable generator. Many people buy a small generator but regret it later because they didn’t understand the basic issues. I’m one of those people.

The generator I’ve used for the last 20 years has a maximum rated output of 3,500 watts. That seemed like enough when I bought it, but it’s proven barely adequate for emergency backup. By the time the submersible well pump kicks in (1,500 watts at start-up), the basement freezer is running (800 watts) and a few lights are on (100 watts for several compact fluorescents), there’s not much power left for other things. If we want to use the microwave or toaster oven, we have to make sure that most other items are switched off. There’s also the issue of sustained output. When manufacturers rate generator output, they usually refer to a maximum, short-term level only. In practice, most generators can sustain only 80 percent of their maximum rating for the long haul. If you continuously demand more than this, you’ll shorten the life of your investment. Unless stated otherwise, always consider advertised generator output as overly optimistic and apply the 80 percent rule.

Because of the reasons listed above, I’m planning to upgrade to at least a 5,000-watt gasoline generator. Unless you have particularly frugal power requirements, you’ll find this to be a good basic size. But there’s still more to know before you buy.

John LeDoux
6/16/2012 3:37:38 PM

There is nothing, use the generator.

susan wood
6/15/2012 2:52:53 PM

just bought a small piece of property in VT and this article on generators couldn't have come at a better time. I had 2 solar systems with 2 big elec start Honda generators in CA but my needs are different now. Noise is a big factor although not covered in this article. Need something to supply basic elec needs while camping during building/ construction. Any suggestions from experience.? (elec start)

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