In general, dual fuel generators will put out less wattage when running on propane than when running on gasoline. That’s unfortunate if you are planning on stockpiling propane for an emergency, but it’s simply a matter of physics – propane is less energy-dense than gasoline. But, if you know how much power you’ll need, you can plan around this by simply opting for a generator that meets your power requirements on propane. Alternatively, if surge wattage is an issue, generators that allow you to seamlessly switch between fuel types can let you start up heavy appliances on gasoline and then run them on propane. We'll help you determine how much propane different generators use as well in another post.