A Guide to Dual Fuel Generators

What are dual fuel generators?

The majority of generators on the market only accept one form of fuel. That means if you own a gas generator and you run out of gasoline, you’re out of luck until your next trip to the gas station. Some generators, however, run on more than one source of fuel. These dual fuel generators are most often portable generators that can run on gasoline or propane.

Dual fuel generators allow you to choose your fuel source based on fuel availability, your power output requirements, noise restrictions, and other circumstances. They are ideal for people with variable power needs. Some dual fuel generators can be used as backup power for homeowners during outages. They are also well-suited to campsites and worksites, as well as industrial areas.

If you’re interested in buying a dual fuel generator, it’s important to first understand your power needs. The brand, model, and size generator you buy should depend in part on how much power you will need your generator to produce. To determine your power needs, try using AlltimePower’s free Backup Power Calculator. You’ll also have the opportunity to be connected with reputable generator dealers in your area.

Why should I buy a dual fuel generator? 

The obvious advantage of dual fuel generators is their ability to accept two types of fuel. Gasoline and propane have different advantages and disadvantages, and some people would rather use one fuel source in one situation and the other fuel source in another. For example, gasoline allows generators to put out more electrical output, but it is more expensive and harder to store than propane.

This flexibility may also allow you to keep your generator running for longer periods of time. When one fuel source runs low, you can simply replace it with the other source of fuel. This is especially important with gasoline because storing large amounts of the fuel source on your property poses a fire risk. In fact, fire codes generally restrict home gasoline storage to 25 gallons. 

Dual fuel generators are also useful in areas with especially cold winters and hot summers. Gasoline burns better in freezing temperatures than propane, but propane is a better fuel source in hot temperatures. In areas prone to natural disasters, investing in a dual fuel generator may be a wise option because a natural disaster could reduce access to certain sources of fuel. For instance, you may not be able to access gas stations, so having extra canisters of propane at home may keep you from losing power.

When not to buy one

Dual fuel generators aren’t the right choice for everyone. If portability is a major concern for you, you’ll want to compare the size and weight of dual and single fuel generators. Some dual fuel generators are designed with wheels and handles to make them more portable, but they still tend to be heavier and bulkier than their single-fuel counterparts. For maximum portability, you may even want to consider buying a portable solar generator.

If noise level is a major concern for you, dual fuel generators are a better option than generators that only accept gasoline. This is because propane tends to burn more quietly and smoothly than gas does. However, inverter generators are quieter still, and they are more energy efficient. An inverter generator usually produces 54-58 dB, compared to 70-100 dB produced by traditional gasoline-powered generators. For reference, that’s like the difference between the noise of a normal conversation and a lawnmower.

Finally, dual fuel generators tend to be more expensive than either traditional portable generators or inverter generators. They are, however, significantly less expensive than stationary, standby generators. Still, if you decide to purchase a dual fuel generator, you should be confident that you’ll want or need to switch between two fuel sources. Otherwise, it might make more sense to buy a less expensive but equally powerful single fuel generator.

Power output

If you decide to buy a dual fuel generator, it’s important to prioritize what features are important to you. For some people, high power output is a priority. Many sellers will publish their models’ peak power output, or the maximum output a generator can produce, and running power output, or the generator’s average power output. Peak power output on dual fuel generators ranges from 1,000 to 12,000 watts.

Sometimes, a seller will also let you know the power output of their generator on gasoline versus propane. If the seller only publishes a model’s output on gasoline, remember that the power output on propane will be a little less than that on gasoline. In other words, if a generator produces 10,000 watts of power when running on gasoline, it may only produce 9,000 watts when running on propane.

Other factors to consider

In addition to power output, you’ll want to consider dual fuel generators’ fuel capacity and runtime. Dual fuel generators have a gasoline fuel tank that ranges from about 2 to 10 gallons. Larger fuel tanks obviously have a longer runtime, but the generator’s power output and engine can also affect it. A dual fuel generator’s fuel capacity and runtime are only important when running your generator on gasoline; when running it on propane, you’ll simply attach a propane gas canister to the generator.

Another factor to consider when buying a dual fuel generator is noise level. Dual fuel generators produce somewhere between 50 and 90 dB, but most fall between 65 dB and 75 dB. Because the decibel is a logarithmic unit, a 75 dB generator will be twice as loud as a 65 dB one. Remember that a dual fuel generator will be louder when running on gasoline than propane, so stick to propane when you want to keep noise levels down. 

Finally, if you’re planning on moving your generator around a lot, you’ll want to consider portability. Portable dual fuel generators come in a range of sizes and weights. Similar to noise level, portability is often a trade off with power output; more powerful generators tend to be heavier. Some manufacturers, however, try to make their models more portable by including wheel kits and handles. 

The best dual fuel generators on the market

Once you’ve decided which factors are most important to you, it’s time to start researching models. The Westinghouse WGen7500 dual fuel portable generator is a well-designed model that offers a high power output and a runtime of about 11 hours at 50% load. Westinghouse also offers the more powerful WGen9500DF model, which offers a peak wattage of 12,500 watts when running on gasoline. Both models are easily transportable and can be started remotely. They are ideal for usage as home backup power. 

The WEN DF1100 11,000-Watt is another powerful dual fuel generator. It includes six outlets, letting you power multiple machines or appliances as well. This makes it a good option for commercial use. It has a runtime of 8.5 hours at half load. The Firman H03652 is a less expensive option. It has a peak wattage of 4,550, but its five-gallon tank has an impressive runtime of 14 hours. While somewhat heavy, both models come equipped with handles and wheels to make transportation easier. 

For a smaller and less expensive option, consider the Champion 3800-Watt Dual Fuel Generator. At just 122 pounds, it provides a respectable 9 hours of runtime on gasoline. It is also quiet at just 68 dB. The DuroStar DS5500EH Portable Generator is another highly portable option. It has a peak wattage of 5,500 watts and operates at just 69 dB. Both models include wheels and handlebars, making them ideal for RVs and campsites. 

Dual fuel backup generators

Though dual fuel generators are most often portable, it is possible to buy a stationary, standby generator that runs on two fuel sources. These types of generators may be able to run on both natural gas and diesel. Like propane and gasoline, natural gas and diesel both have unique advantages and disadvantages, so being able to switch from one fuel source to the other gives you greater flexibility and control. 

Since natural gas generators are most often connected to natural gas lines, dual fuel backup generators give you the added security of being able to switch to diesel if the supply of natural gas is interrupted. During some natural disasters, such as earthquakes, natural gas lines may burst. They also allow you to choose which fuel source is the least expensive at a given time. The ability to switch to the least expensive fuel is especially useful for businesses and factories trying to cut operational expenses. 

If you’re considering either a portable or standby dual fuel generator, start by understanding your power needs. You can calculate how much power output you’ll need your generator to produce by adding together the starting wattage of all the appliances you’ll want to power. Alternatively, you could use AlltimePower’s free Power Calculator. After estimating your power usage, you’ll have the option to connect with reputable generator dealers in your area.

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