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As a group, inverter generators outperform their conventional counterparts. They provide better run times, improved efficiency, and much quieter operation, whether you’re using one at home or at a tailgate party.
But that doesn’t mean all inverter models are created equal. Far from it, according to Consumer Reports’ tests. Those tests include traditional gasoline-powered portable generators as well as inverter generators, and home standby models.
“Even with inverter models, we see big differences in how well generators deliver power,” says Dave Trezza, who oversees Consumer Reports’ generator testing. “Especially when they’re pushed to extremes.”
How a portable inverter generator operates at peak demand is important. A model that can’t keep up with your power needs may trip its own internal circuit breaker or cause your appliances to overheat or stall out—a phenomenon we routinely witness in testing. If you end up with a generator that falters during peak demand, you’ll need to unplug some appliances when you plug in others. You’ll also need to reset the generator’s circuit breaker each time you do.
How We Test Generators
For each generator, we connect a combination of lights, space heaters, and fans—appliances that draw a constant load—then tack on a power-hungry well pump and program it to cycle on and off at set intervals.
Some generators can meet demands immediately, only to fail and trip their own circuit breaker later. So we run this test for an hour, metering wattage, voltage, and amperage. If a model passes, we repeat the test twice more, adding 1,000 watts to the load each time. That’s just for the power delivery rating, one of four that make up a model’s Overall Score.
The best generators deliver power to all the devices in our tests, at full voltage. The worst models won’t even power a basic load of lights and fans.
We also developed a CO safety technology test to evaluate new automatic shutoff features on portable and inverter generators—though we haven't yet tested any inverter models with the technology.
Our ratings of dozens of models include the brands you’ll see whether you’re shopping online or at home centers: Briggs & Stratton, Generac, and Ryobi.
Start with our buying guide for advice on which kind of generator you need. CR members can read on for ratings and reviews of our top three inverter generators, one from each of the three size categories. Currently, none of the large inverter generators in our ratings come equipped with a carbon monoxide shutoff, a potentially life-saving device that turns off a generator when it's operated in an enclosed area. CR plans to test large inverter models with CO safety shutoffs soon.
Below, we highlight a large inverter model that performs well in our tests, but it doesn't have a shutoff. We also call out a large inverter model to skip. Not only does it lack a CO safety shutoff, it's also among the worst-performing models we've tested.
Consumer Reports only recommends gasoline-powered generators that are designed to produce low levels of carbon monoxide, or which have an automatic shutoff mechanism, to turn off the generator in the presence of excessive carbon monoxide. Currently, none of the inverter generators in our ratings have either of these potentially life-saving features, but the models below fare extremely well in our performance tests. With any generator, it’s extremely important to follow our longstanding advice of always operating a generator a minimum of 20 feet from your house, with the exhaust directed away from any windows, doors, or air conditioners.
Worst Inverter Generator in CR's Tests
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