Portable generators come in different sizes
Portable generators provide electricity when you're off the grid, or when the grid goes offline. As you consider your wattage needs, it's helpful to know that portable generators fall roughly into three size groups:
- 750 to 3,500 watts: These generators are small enough to carry onto a boat or to a campsite. At the top end, they can keep a few appliances running simultaneously during a power outage, including a refrigerator, several lights, and a computer or TV. For electronics, the safest bet is an inverter generator, which maintains consistent power and prevents electrical surges that can damage computers and televisions.
- 4,000 to 8,000 watts: Generators of this size provide enough power for extended emergency use for a 1,200- to 3,000-square-foot house. The exact size needed will depend on how many appliances you think are essential to run simultaneously.
- 10,000 to 17,500 watts: These generators are large enough to provide backup power to larger homes.
Manufacturers list two wattage levels for each portable generator:
Running or continuous wattage, sometimes called rated wattage, is how much power the generator continually produces.
Peak wattage, also called maximum or starting wattage, is a measure of how much peak electricity your generator can provide to get large appliances and other power-hungry devices started while still running everything else that's plugged in.
In this report, we cite the continuous wattage unless otherwise specified.
Not all portable generators produce surge-free power
A few portable generators have voltage regulators or inverters that make their energy "clean" enough to power delicate, expensive electronics like your computer or flat-screen TV. In other words, the generator offers a consistent, surge-free supply of electricity. Generators that lack regulators or inverters may produce occasional power surges that could damage electronics.
If you live in California, you'll need a generator that complies with the California Air Resources Board (CARB) regulations. You don't have to purchase CARB-compliant generators if you live in other states, but they do produce lower emissions.
Powering up a portable generator
Portable generators don't switch on automatically; you must wheel or carry them out of storage, make sure they're fueled and start them manually. All portable models have a recoil or pull-cord starter, just like the cord you'd pull to start a lawn mower. Some also have a push-button electronic starter that's powered by a small, internal battery. An electric ignition won't work if the battery goes dead, but you always have the pull cord as backup.
Assembly and warranties
The portable generators we evaluate range from a 44-pound model that's small enough to carry by hand to wheeled models that weigh nearly 400 pounds. While a portable generator's mechanical components come fully assembled, you must attach the wheels and handles yourself. For the largest generators this may require a floor jack, although some owners use levers or recruit strong friends to help them move the parts into position.
Portable generators typically come with one to three years of warranty coverage, but numerous owners warn that a warranty won't do you any good if the manufacturer never responds to your concerns. Complaints about poor customer and warranty service are particularly common with Generac models.
That said, many owners of all brands dislike having to take their generator to a designated service center for warranty service. If you purchase a large generator, transporting it to and from the service center can pose a major logistical challenge.
Portable generator jargon
Portable generators typically have two or more electrical outlets, and the better ones will have different types. You'll see these figures on many portable generator spec sheets. Most electronics and kitchen appliances plug into standard 120-volt outlets, the kind you'd see in any house. These are rated either 5-20R or 5-15R. Larger appliances, such as clothes dryers and big window air conditioner units, require a 240-volt outlet. These are sometimes called twist-lock outlets.
Ground fault circuit interrupter (GFCI) outlets, available on some high-end generators, offer an extra layer of protection against electrocution by continuously monitoring power flow through the outlet. In the event of a ground fault -- basically, you getting electrocuted -- they're designed to cut power to that outlet in a fraction of a second.
A few of the generators we evaluate can produce DC current in addition to their AC output. The most common household use for DC current is charging automobile or RV batteries.
Portable generator review sources
We found a few comparative reviews of portable generators in magazines like Camping Life, but user feedback is our best source for gauging a machine's real-world performance. However, it pays to be careful about which critiques you read. Almost all reviews for Generac models posted on websites such as HomeDepot.com, NorthernTool.com and TractorSupply.com are sourced from Generac's website, which might not be so impartial. In cases like this, we ignore the redundant or apparently biased comments.