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Gas vs Propane Generator (2021): Which Portable Generator Should You Buy?

Choosing your backup power source should start from deciding which fuel type you’ll be relying on. The most common types of generators run on either gasoline or propane, though there are now a lot that can also run on both. We compare different 10,000-watt models below to show the pros and cons of gas and propane generators and help you decide which one to get. Here’s a look at the Westinghouse WGen9500, the All Power America APG3590CN, and the DuroMax XP10000EH.

Gas vs Propane Generator Comparison Chart

ModelWestinghouse WGen9500All Power America APG3590CNDuroMax XP10000EH
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TypeGasolinePropaneGasoline, Propane
Engine4-Cycle OHVOHVOHV
Starting SystemRecoil, electric, remoteRecoil, electricRecoil, electric
Max AC Output12,500 W10,000 W10,000 W
Rated AC Output9,500 W7,500 W8,000 W
Voltage120V / 240V120V / 240V120V / 240V
Max AC Current104A (120V) / 52A (240V)n/a83.3A (120V) / 41.6A (240V)
Rated AC Current79A (120V) / 36A (240V)n/a66.6A (120V) / 33.3A (240V)
DC Output5V12V12V
Fuel Tank Capacity6.6 gal5 gal8.3 gal
Run Time12 hrs at 50% load8 hrs at 50% load8-10 hrs at 50% load
Noise Level73 dB75-77 dB72 dB
Low Oil ShutoffYesYesYes
Dimensions27.2″ x 26.1″ x 26.5″29.5″ x 23″ x 22″30″ x 29″ x 26″
Weight220 lbs208 lbs232 lbs
Warranty3-Year Limitedn/a3-Year Limited

Engine and Power

Gas generators typically produce more power output than propane generators.

Gas vs Propane Generator Engine and Power
The Westinghouse WGen9500 (left) only runs on gasoline while the All Power America APG3590CN (right) only runs on propane.

The fundamental difference between these two types of generators are, of course, in what type of fuel they require. In general, gasoline produces much more BTUs per gallon of fuel compared to propane, making them the more efficient fuel type. As such, gasoline-powered generators tend to be capable of producing a higher kilowatt output than propane generators, considering similar displacement and engine specs.

You’ll generally find gas generator models, such as the Westinghouse WGen9500, to list higher starting and running wattage than propane generators like the All Power America APG3590CN. The Westinghouse model has a maximum AC output of 12,500 watts, allowing it to start more heavy equipment, and a running wattage of 9,500 W, enabling it to run more appliances simultaneously. In comparison, the All Power model maxes out at 10 kW and only has a rated output of 7.5 kW.

Generators that can run on both gasoline and propane make this comparison more interesting, since they provide another alternative for people looking for backup power. Since most of these hybrid generators need more complex fuel assemblies than standard gas generators, they tend to provide similar outputs as propane generators. For example, the DuroMax XP10000EH has a starting and running wattage of 10 kW and 8 kW, respectively, while it’s running on gasoline, and this drops by 400 to 500 watts if it’s running on propane.

Because gasoline produces up to 30% more heat than propane, gas generators will need to consume less fuel than a propane generator to produce the same amount of power. This translates to longer run times in general, since gas generators will use up its fuel supply slower than propane types. Filling up the 6.6 gallon tank of the Westinghouse WGen9500 lets it run up to 12 hours on 50% load, while connecting a 20-lb propane tank, which carries about 5 gallons of fuel, to the All Power America APG3590CN gives you 8 hours on the same load.

Convenience and Safety

Propane generators benefit from safer and longer-lasting fuel, but gas generators are easier to find fuel for.

Gas vs Propane Generator Convenience and Safety
Hybrid generators like the DuroMax XP10000EH give you the flexibility of choosing your fuel.

Perhaps the best advantage of propane generators is how its fuel is stored and injected into the engine itself. Propane is kept inside sealed tanks and cylinders that make them safe to stockpile. These tanks can be easily connected to the engine, and you can connect multiple tanks together to provide more fuel and enjoy a longer run time for your generator. The best part is, propane can be stored for a very long time, as it has an average expiration of 12 years. That means you can keep several tanks in the shed so you can be ready for the next power outage, even if it’s years in the future.

In contrast, gasoline can only last 12 months before it starts degrading. Keeping large quantities is also unsafe as it’s extremely flammable and it isn’t typically stored in sealed containers. Gasoline also produces unpleasant and dangerous fumes, and you’ll have to pour it into the generator’s fuel tank every time. This needs to be done with care so as not to spill any amount that can catch fire later.

Still, in terms of accessibility, you’ll find it much easier to get gas than propane during normal times. Any number of gas stations can supply you enough to run gas generators for a while, and it’s easy to transport too. Propane tanks, on the other hand, are very heavy, and the places where you can get them are fewer and farther in between. You’ll have a tougher time getting restocked as well as moving the tank to where your generator is.

Note that natural disasters such as earthquakes, blizzards and hurricanes can impact gas supply worse than propane. People will tend to fill up their cars and trucks, and stock up on extra gasoline during crises like these, so it can get more difficult securing fuel for your gas generator. Propane tanks won’t be under the same demand though, so relying on a propane generator for backup power during emergencies can be more attractive and secure.


Gas generators tend to cost less on average, but propane generators have a lesser impact on the environment.

Gas vs Propane Generator Fuel and Environmental Costs
Using generators carry both monetary and environmental costs.

Today, you’ll be able to find gas-powered generators much more easily than propane generators. In addition, they’ll typically be priced lower when comparing kilowatt generation, though this of course is still highly dependent on the brand. Gasoline and propane prices won’t be influenced by generator brands though, so you can compare fuel costs more accurately and fairly.

Though gas tends to be cheaper than propane in most places, you’ll want to compute how much you’re spending per kilowatt-hour your generator is able to produce. Based on average US prices, propane can cost twice as much as gasoline per kilowatt-hour of generated power. You’ll want to check your local area’s fuel prices to get a better idea of how much the cost difference will be when choosing your generator fuel type.

Using generators does have an environmental cost in addition to financial, since you’re burning fuel which produces harmful emissions. Here propane definitely has the upper hand, as it’s a clean-burning fuel compared to gasoline. It produces very low carbon monoxide amounts which make it easier on surrounding plants, animals, and people.

Dual-fuel generators like the DuroMax XP10000EH can be a nice option since you can switch fuel types depending on the situation. You can use gasoline for recreational activities or immediate power outages, and rely on propane if its goes on longer. However, since they have more complex machinery, they can be more difficult and costly to maintain and repair, so make sure you have an authorized service dealer nearby for your hybrid.


Gas generators are better for regular use while propane generators are better for backup power.

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Because gasoline is cheaper and more accessible, gas-powered generators will tend to be better if you plan to use it regularly, such as for camping, tailgating, etc. Gas generators like the Westinghouse WGen9500 produce more power and can run for longer, supplying your home, cabin, or party enough to run most appliances and equipment. You’ll want to get gas with little to no ethanol content though, and ensure that the gas in its tank doesn’t get stale when left unused too long.

As a backup power source, a propane generator like the All Power America APG3590CN can be more reliable, especially for power outages that extend for several days or even weeks. Propane tanks are safer and cleaner to store, so you can keep a nice supply that remains usable for several years. If used regularly, propane generators will have a reduced environmental impact and won’t produce harmful fumes if installed correctly.

Finally, you also have the option of going for a hybrid generator like the DuroMax XP10000EH which can run on both gasoline and propane. You get the best of both worlds, combining the cost-effectiveness and ready availability of gas with the dependability and safety of stored propane tanks. You’ll want to ensure that you’re following good maintenance habits though, since these can become costly to repair if something does break.

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Derick Bondoc

Managing Editor at Compare Before Buying. Writer and researcher passionate about gadgets, gaming and snacks.