Whether you use a generator to make camping more convenient or to run your appliances during emergency situations, there are a few things you need to know.
Among the most important considerations is how much gas does a generator use? More specifically, how long will a generator run on one gallon of gas?
Knowing the answers to these and other important gasoline generator fuel consumption questions helps ensure you are adequately prepared.
By learning more about gasoline generators and how they are expected to function, you can also make better purchasing choices.
Lastly, you can learn the best ways to use your generator efficiently and safely by getting more educated about the functionality of gas generators.
Getting to Know Generators
Before we talk about the specifics, it’s essential to know that different types of generators use different fuel types.
Excluding inverter generators, most units run on one of these four fuels:
- Propane
- Diesel
- Natural gas
- Gasoline
Each fuel type has its pros and cons, which you should research in more detail before buying your generator.
What is more important to understand is that each type of gas also has different use times.
The length of time you can use your generator depends on how efficient your unit is and the type of fuel it uses.
Keep this in mind while learning more about the run time and fuel use of generators.
How Much Gas Does a Generator Use per Hour?
As mentioned, different generators use different types of fuel.
Essentially, this means that each generator, even if it is rated for the same wattage, will use a different amount of fuel.
In fact, a generator’s run time will vary based on different factors, including fuel type, efficiency, load, design, and more.
Average Gasoline Generator Fuel Consumption
Still, it is possible to average out the expected amount of gas used in a standard gas generator.
Gas generators are the most commonly used type of generator, so it makes sense to base the average off of that data.
A 5,000-watt standard generator will burn around 0.75 gallons of gas hourly.
Running the generator for a full day would burn 18 gallons of gas, though most generators do not have a big enough gas tank to run at full capacity all day.
Of course, a 12,000-watt standard generator would burn more gas every hour.
To get the most comprehensive idea of what you can expect from various generators, you must consider each generator type separately.
Gasoline
Got a generator that runs on gasoline? A 5kW gas generator eats up around 0.75 gallons of fuel per hour.
Propane
How much propane does a generator use? On average, a 5kW propane generator uses around 1.3 gallons of fuel hourly.
Diesel
If you have a diesel generator rated at 8kW, it should burn roughly half a gallon of fuel every hour.
Natural Gas
Natural gas generators rated around 5kW burn roughly 100 cubic feet of fuel hourly.
How Long Will a Generator Run on One Tank of Gas?
Generally speaking, standard generators are usually rated to run for between eight and 12 hours at 50% load.
If a generator is fully loaded, it will likely run for less time than this on one tank of gas (unless it has a very large gas tank).
The exact answer is going to vary depending on a few different factors.
When trying to figure out how long one tank of gas will last, ask yourself these questions:
1. What type of fuel does the generator use?
As mentioned, different types of fuels have different burn times and efficiency ratings.
The type of fuel plays a considerable role in how long a tank of gas will last.
While gas generators are the most commonly used due to how convenient they are to use, gas is the least efficient fuel type.
On the other hand, propane is known to be one of the most accessible. Like propane, diesel is very efficient, as well.
2. How big is the tank?
Aside from fuel type, another factor that will affect how long a generator will run on one tank is, obviously, the tank size.
A generator with only a two-gallon tank is not going to run for as long as a generator with a four-gallon tank.
In that case, finding a generator with the right tank size for your needs is very important when setting up one.
If the tank size is too small, you will need to refill it frequently, which can be impossible or inconvenient in some cases.
3. What is the energy load?
Finally, the amount of energy load that a generator experiences will affect how long it can run.
If the full output is being used, and it is running at a 100% load, the run time will be significantly reduced.
Most manufacturers will explain how long a generator can be expected to run at maximum load and at ¼ load.
You can then use this information to calculate what you need to know.
Calculating Your Use Time
Once you have that information, you can calculate your expected generator use time by following these steps:
Step 1: Determine the fuel type and write down how many gallons of fuel are used each hour.
Step 2: Divide the fuel tank size by the number from Step 1.
Step 3: The resulting number is how long you can expect the generator to run when operating efficiently.
If you can’t figure this information out, another way to find out how long your generator will run on a full tank of gas is to simply let it run.
While this isn’t the best way to find out, it will let you know exactly how long will a generator run on one gallon of gas.
Why Is My Generator Using So Much Gas?
Sometimes, you might feel like your generator uses a lot more gas than it used to or more than it should.
In some cases, this might be because of an operating error or something going wrong with how you have the generator set up.
Here are some troubleshooting tips to help work out the overuse.
Problem #1: Degrading Quality
If you’ve had your generator for some time, there may be some small mechanical problems going on. These problems can cause reduced fuel efficiency.
Simple things such as the buildup of fuel or oil in the generator lines can lead to inefficiency.
The Solution
Make sure that you are following the manufacturer’s maintenance and cleaning recommendations.
If you need to turn off the generator, check that the fuel is completely and cleanly burned out.
If possible, take your generator to be serviced at a local shop every two or three years to improve long-term efficiency.
By taking simple actions to ensure that your generator is being maintained properly, you will see a huge return in fuel savings.
Problem #2: Not Using Enough Power
Though it can be consuming, it is actually possible that you will be less fuel-efficient when using less power.
Most generators are made to run most efficiently when they are operating above 50% capacity.
This means that you could burn just as much fuel using only 30% of the generator’s power as you would running it at a 50% load.
The Solution
One modern solution to this problem is to switch to an inverter generator.
This type of generator still runs on fuel, but it changes the generator's speed to better match the power needed.
When less power is being used, the generator runs slower. This allows the generator to burn less fuel and also make less noise.
Inverter generators are becoming more and more common among standard generator offerings, so it is likely to be the norm in the future.
Problem #3: Overloading With High-Use Appliances
In some cases, you might be burning through more fuel than expected because you are overloading the generator more than usual.
Most people only use between 50% and 75% of their generator when it is running.
That is good because most standard generators run most efficiently when running between 50% and 80% of capacity.
If you start running appliances that are high-wattage or run multiple appliances at once, that could change. And that change will increase fuel consumption.
The Solution
When running electric appliances off of your generator, consider which appliances use more energy than others.
Running a dryer on a generator, for example, is going to consume a lot of power.
Find ways to cut back on the number of appliances you use at a time or skip using them altogether to lower fuel consumption.
Still, you have to remember that you want to keep the usage above 50% to keep the generator running as efficiently as possible.
Get Going With Your Generator
Finding out how much gas does a generator use can be a complicated process, especially since there are many factors that will affect that number.
Ultimately, the average gasoline generator fuel consumption rate of 0.75 gallons of gas per hour is a good number to use as your baseline.
From this number, you can create a reasonable estimate for gas usage.
Another great way to stay on top of knowing how much gas your generator should use is to pay attention to the manufacturer’s guidance.
If you have any questions about usage, contacting the manufacturer directly is a great way to determine things.