Running a sump pump or just turning on a lamp -- there's a generator for that!
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 more or less fall 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 TV.
4,000 to 8,000 watts. Generators of this size provide enough power for 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. For example, at 4,000 watts you could probably run a window air conditioner or the fan for a gas furnace (but not an entire electric furnace), at the same time as a refrigerator and other appliances. At 8,000 watts, you could add an electric hot water heater.
10,000 to 17,500 watts. These portable generators are large enough to provide essential power to larger homes, even for extended power outages. At the top end, you can even run an electric furnace, heat pump or central air conditioning.
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.
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. We cover inverter generators that are safe for electronics elsewhere in this report.
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.
Starting and using a portable generator
Unlike standby generators that are permanently wired to your house, portable generators don't switch on automatically. With portable generators, 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 on most lawn mowers. 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.
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, kitchen ranges 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.
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 typically 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 many owners warn that a warranty won't do you any good if the manufacturer never responds to your concerns, an issue that does crop up in some user reviews. In addition, you may need to transport your generator to a designated service center for warranty service. If one is not nearby, or if you purchase a large generator, transporting it to and from the service center can pose a major logistical challenge.
Finding the best portable generators
ConsumerSearch editors evaluated dozens of expert and owner reviews for every type of portable generator sold. From there, we narrowed it down to the models with the top reviews for features, performance and ease of use. Price was a consideration as well, and we found one highly rated generator that costs only $200. One of these generators will be sure to keep your power on as long as you need it.
Best Portable Generators
The best portable generator will tide you over until the power comes on
A basic, portable generator should be able to provide enough power to cover your home electrical necessities in an emergency. Experts say a generator that supplies 5,500 watts is about the right size for most situations. That's enough to power a few critical appliances, such as a refrigerator, gas furnace fan, microwave and some lights. Using basic generators to power electronics isn't a good idea; they can create power surges that will fry a TV or computer (see our section on inverter generators to find one that's safe for electronics).
Reviews say an ideal combination of mid-grade power, convenience and value makes the Generac GP5500 (Est. $700) the best overall portable generator. Its 5,500 watts of continuous power -- and 6,875 watts of start-up power -- provide sufficient backup electricity to get you through an emergency.
In expert tests, the GP5500 performs beautifully. It's named a "best buy" by a leading consumer organization. Testers say it's easy to use and delivers strong, smooth, consistent power, just as well as -- or better than -- generators costing hundreds or even thousands more. In a test at Popular Mechanics, editors find no flaws; they especially appreciate the included dipstick and large oil-fill opening, which make the GP5500 easy to service.
Owner reviews aren't consistent, though. Most owners like it, saying the GP5500 usually starts with just a couple of pulls and has gotten them through some tough power outages. However, several users, primarily those posting at Amazon.com, complain of horrible customer service in their reviews, saying Generac won't honor its two-year warranty on this generator. This would normally be a red flag, but feedback elsewhere is far more positive. While reviews at HomeDepot.com include many that were originally posted at the manufacturer website, nonetheless the GP5500 receives a 4.7-star rating from more than 630 users, with 97 percent offering it a recommendation. At ElectricGeneratorsDirect.com, the GP5500 receives a recommendation from product expert Mike Sawisch, and generally good reviews from around 170 owners -- 95 percent give it a thumbs up, and the generator rates 4.8 stars overall.
Stepping up to a generator with a higher wattage output gives users the ability to run more appliances and/or larger appliances, such as an air conditioner. The downside is that larger generators are typically heavier and are notably louder -- still, you might be able to get away with using one of them if there's plenty of room between houses, especially if you share some of your power with your neighbor. Larger generators are also less fuel-efficient, though a 7,000- to 8,000-watt model will typically burn less than a gallon of gas per hour.
The Westinghouse WH7500E (Est. $900) produces 7,500 continuous watts and 9,000 watts of starting power. Bonus features include a one-touch electric start, a Pulse-Flo muffler for quieter operation and a longer three-year warranty. Its low-emission design meets CARB requirements for California users. Just like the GP5500, the Westinghouse has five outlets, one of which is a twist-lock style to run 220-volt appliances like air conditioners and clothes dryers. It performs excellently in an expert test, where it's judged a bit quieter than the Generac GP5500. The Westinghouse also gets consistently good owner reviews. However, it costs $200 more than the Generac and lacks outlet covers for extra protection during storms.
"Portable" becomes a formality of sorts when you're talking about monsters like the 390-pound Generac GP17500 (Est. $2,430). Even with its wheels and handles, you'll want a floor jack to assemble it, and moving it any distance requires a trailer or a lot of muscle. The trade-off for that massive weight is massive power. Offering 17,500 continuous watts and 26,250 watts of starting power, the GP17500 can easily power an entire house, running central air conditioners and geothermal heat pumps. The downside? It comes with a noise level to match and burns more than a gallon of gas per hour, so it's a reasonable option only if you actually need and use its full power capability.
Cheap portable generators provide power on a budget
For a simple portable generator, light-duty models capable of running a few appliances at a time are available for less than $500. This class is best for homeowners or campers looking for an occasional backup generator at a good value. "Because of their simplistic design and construction quality, [they] typically don't last many hours, nor can most take the abuse of a typical worksite," explains Pam Meyer with Contractors Equipment Directory, a trade magazine for the heavy construction industry. These light-duty generators are built for easy homeowner operation in an emergency, but not for supplying heavy-duty power or for longevity, says Meyer.
Only a few portable generators are inexpensive and yet still reliable enough to start up after sitting dormant for a few months. Champion stands out in this class, and reviews say the 1,200-watt Champion 42436 (Est. $200) is one of the best portable generators available. The 42436 includes an impressive list of attributes, such as a fuel gauge and a fuel shut-off valve that helps drain gasoline from the carburetor, that aren't typically found at this price range. Owners say the Champion 42436 is user-friendly, and it draws compliments for its build quality as well. Still, with its low wattage output (and only 1,500 watts of starting power) and just one 120-volt receptacle, the 42436 has limited powering abilities -- some small appliances and household items, the Champion web site says.
The Champion 46596 (Est. $350) expands users' options, with 3,500 continuous watts and 4,000 watts of starting power. In addition to a standard outlet, it has an L14-30R outlet (which can accept a special extension cord with splitter, so that several appliances can share the outlet) and a TT30R outlet that's compatible with RVs and travel trailers. It's a bit louder, nearly twice as heavy and guzzles more gas than the 42436, but owners say it's just as durable. Champion protects both the 42436 and the 46596 with a low-oil shutdown sensor. The brand's two-year limited warranty is excellent coverage for generators in this price range.
Propane generators are easy to maintain
Gasoline is an inexpensive fuel for powering tools, but not necessarily the most convenient one. Maintenance for a gasoline-powered generator includes always having fresh fuel on-hand, using a fuel stabilizer and either running the engine once a month or draining the fuel tank and lines. "Propane-powered portable generators solve these problems and more," say editors at The Family Handyman. "You can store and use liquid propane indefinitely (it doesn't go bad). Refueling is simple and safe; just replace the propane tank with a full one. And you don't have to worry about the carburetor on your generator getting gummed up with old gasoline."
Reviewers say the propane-powered, 3,250-watt Generac LP3250 (Est. $650) provides the best balance of power, performance and genuine portability. Owners, particular those posting at Amazon.com, say customer support for this model isn't great -- among other things, not all Generac-authorized service centers will work on propane models -- but they love not having to wait in long lines for gasoline during a shortage. It's powerful enough to run a sump pump, but not quite beefy enough to power a clothes dryer. However, most reviewers agree it can run the essentials for a few days without power.
The LP3250 has four 5-20R outlets and a single 20-amp 120/240-volt twist-lock outlet. Customers say everything in this price range is noisy, but owners say the LP3250 is quieter than the gas-powered models. It accepts 20- or 30-pound tanks of propane, and they mount directly onto the generator. Generac estimates nine hours of run time at half load on a 20-pound propane tank, and most owners say the results are even better. Reviewers say the fuel changes are quick and easy compared to gas-powered machines and that the LP3250 is highly maneuverable. One negative is that propane generators -- including the LP3250 -- can be harder to start than gasoline models, a problem that's notably worse in cold weather.