How long can a propane generator run

There are a lot of different factors to consider when shopping for a generator. Fuel consumption is one of the first and foremost. You want to feel confident that your generator will continue to operate during an extended power outage in your area. Understanding the different types of fuel, generator capacities and how long your Generac generator will continue to run on a single fuel supply will help you choose the right model for your home.

Different Types of Fuel 

In the past, generators relied heavily on diesel fuel. However, there are now cleaner alternatives that are safer for the environment and easier to store. Today’s modern generators use propane and natural gas to provide continuous service. These models cleanly burn fuel and can be connected to the home’s natural gas lines or larger propane tanks for a constant supply of fuel. 

Generac Generator Fuel Consumption Rates

How much fuel is consumed and how quickly depends both on the size of the generator and the amount of load it is supporting. Fortunately, a Generac specialist will be able to recommend the right size generator based on the square footage of your home, whether you want to power the entire home or only certain systems or appliances and the approximate amount of time you expect to be running your generator. 

Just as an example, a 22 KW Generac generator will burn through 9.7 cubic meters of natural gas when operating at full load. If it is directly hooked up to your natural gas lines, you will be able to keep your home up and running for an indefinite period of time. 

As for another example, again depending on what you are powering and the size of your generator (let’s say 20kw in this example), a propane generator may use around 2-3 gallons/hour. So, if you have a 500-gallon tank, which can only be filled to 400 gallons, then a full tank would last you around 6 to 7 days. Again, these are all rough estimates and a true estimate of generator fuel consumption rates would need to be given by a Generac specialist after they take into consideration what you plan to power and the type of fuel you plan to use.

If you would like additional information about Generac generator fuel consumption rates and expert advice on which models are best for your home and your needs, contact the team at Alternative Power. Our highly trained and experienced technicians can answer all your questions on Generac fuel consumption.

Generators stop working when they run out of gas. That’s why we looked into how long will a generator run on 5 gallons of gas.

Here’s the short answer:

A generator on 5 gallons of gas will last anywhere from 6 hours and 42 minutes to 363 hours and 19 minutes. The exact time primarily depends on generator size, and secondarily on the choice of fuel (gasoline vs. propane).

That’s quite a range. How to figure out how long will 5 gallons of gas last in a generator exactly? Well, we need to calculate a bit, based on several factors.

To help you out, we have prepared a ‘5-Gallon Tank Generator Running Hours Calculator’ where you can insert the max. running wattage of your generator, and choice of fuel (gasoline vs. propane), and it will calculate how many hours such a generator lasts on a 5-gallon gas tank. Below the calculator, you will also find a calculated chart of how long does a 5-gallon tank lasts for 500W to 20,000W generators.

Here is what the calculator looks like (you can find it further on):

The 3 most important factors that determine how long will 5 gallons of gas last in a generator are:

1. Size of the generator. A bigger 10,000W generator will run out of gas much faster than a small 2,000W generator.
2. Generator load. If you run a generator on 100% output running wattage, it will burn through the 5 gallons of gas faster than if you would run it on 50% running wattage.
3. Choice of fuel: Gasoline vs Propane. 1 gallon of propane can generate up to 91,500 BTUs. 1 gallon of gasoline can generate up to 124,000 BTUs. That means that a gasoline generator will run 36% longer than a propane generator (if we presume the same energy efficiency).

To adequately calculate the running time of a generator on a 5-gallon gas tank, we need to first determine the energy content of both gasoline and propane:

Energy Content Of Gasoline And Propane

Generators run on either gasoline or propane.

5 gallons of gasoline contain 620,000 BTU of energy. If we convert BTUs to watts (1 BTU = 0.293 Watts), we can get up to 181,660 watts out of 5 gallons of gasoline.

Example: That’s enough to run a 10,000W generator for 18 hours and 10 minutes. If you have a smaller 2,000W generator, 5 gallons of gasoline can run it at 100% load for almost 91 hours; that’s almost 4 days.

5 gallons of propane contain 457,500 BTU of energy. That’s 134,048 watts of electrical energy.

Example: With a 5-gallon propane tank, we can run a 10,000W generator for 13 hours and 24 minutes. A smaller 2,000W generator can use that energy to run for 67 hours and 1 minute; almost 3 days.

Standard generators do give 100% output all the time. Inverter generators, on the other hand, adjust the power output to the power draw; they will last longer on a 5 gallon of gas.

5-Gallon Tank Generator Running Hours Calculator

Using this calculator, we can calculate exactly how long will a 5-gallon tank last for different generator sizes:

Calculated Table For Different Generator Sizes (5-Gallon Tank)

Hopefully, you can now adequately estimate how long will a 5-gallon tank run a generator.

If you have any questions regarding the calculations or your specific generator, you can use the comments below and we’ll try our best to help you out.

• Energy Content Of Gasoline And Propane
• 5-Gallon Tank Generator Running Hours Calculator
  • Calculated Table For Different Generator Sizes (5-Gallon Tank)
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