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 score, 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.
Our ratings of dozens of models include picks from the brands you’ll see both online and at home centers, such as Briggs & Stratton, Generac, Honda, Honeywell, Kohler, NorthStar, Predator, Ryobi, Troy-Bilt, Westinghouse, and Yamaha.
The prices for generators in our ratings range from $430 for a modest recreational generator to $4,300 for the top-rated large, stationary model.