How Much Propane Does a Generator Use

On average, a propane-powered generator can consume about two to three pounds of propane hourly. Propane generators are an excellent option for backup power when needed more permanently than solar panels or batteries. For the sake of preparing for emergencies, it is sensible to learn how to calculate or estimate how much propane your generator consumes depending on the number of hours you will be running the generator. This information will help you in planning how much propane you need to store before the emergency strikes. Read on this article to learn more about factors that influence propane gas consumption and calculate the consumption rate.

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Key Determinants of How Much Propane Does a Generator Use

It’s important to understand that not all generators are created equal – some have higher fuel efficiency ratings than others. How much propane your generator will consume depends on:

The Size of Generator

How much power a generator produces correlates with the physical size of the generator, which is also proportional to the engine size. Generators big in size have a bigger engine responsible for generating more power output than a small engine generator.

A big generator will consume more propane than a small one because it has a big engine that delivers higher power output.

Operation Mode of Generator

The number of hours you operate your generator may also affect how much propane it can use. The longer you run the propane generator, the more it will consume. If you are using the generator to power your entire house, expect to use more propane instead of if you plan on running it for an hour or two.

Age of Generator

Another factor that determines how much propane a generator can use is the age of the generator. Older generators have parts that are worn out and corroded – this reduces the engine’s efficiency, which has an impact on how much propane it consumes. A new generator will consume less propane than an older model, even if it is the same size.

Load on the Generator

If you plan to connect appliances with high power consumption to the generator, expect that it will take more propane. If you run a refrigerator, space heater, and other appliances together, the generator will work hard to deliver such high energy demands making it use more propane. Any appliance that makes use of lots of energy will consume more propane than appliances that do not make use of much energy like televisions and lights.

How to Calculate Total Propane Consumption

Before you know how much propane you will store, you need to know how much propane your generator uses per hour. Once you get the hourly consumption, multiply it by the number of hours you intend to run the generator. Add a few hours for emergencies.

Total propane = hourly propane consumption X number of working hours + a few hours for emergency

How to Calculate Hourly Propane Consumption Rate

Before proceeding with these calculations, here are assumptions to make:

  • A gallon of propane weighs 4.2 pounds
  • The fuel value of propane is 92,000 BTU per gallon
  • A 2-horsepower generator delivers about 1,000 watts of power output
  • 1-horsepower requires about 10,000 BTU per hour of fuel

Easy Steps to Follow

Step#1: Calculate how much horsepower we’ll be using;

To get the horsepower, divide the total wattage (your load) by 1000 and multiply the results by 2

Horsepower = (watts/1000) X 2

For instance, if you have a power demand of 3000 watts, you would need a horsepower of 6. Here is the calculation:

HP = (3000/1000) X 2

= 6

Step#2: Calculate how many BTUs are required for the load (3,000 watts) in step#1:

BTU = Horsepower X 10,000

= 6 X 10,000

= 60,000

From our example, a 3,000-watt load will require fuel that generates about 60,000 BTU per hour.

Step#3: Calculate how much (gallons) propane corresponds to the results in step#2:

To get the number of propane gallons required to generate 60,000 BTU per hour, divide the BTUs by the fuel value of propane (92,000 BTU per gallon).

Gallons of Propane = 60,000/92,000

= 0.65 gallons of propane per hour

Therefore, you will need 0.65 gallons of propane to run a 3,000-watt load generator for an hour,

Why You Should Consider Buying a Propane-Powered Generator

How Much Propane Does a Generator UsePropane is a famous energy source for people looking for clean energy sources. Propane produces a lower level of carbon monoxide gas when compared to gasoline. Besides being environmentally friendly, here are other benefits for using propane as your preferred fuel source for your generator:

Propane gas has a long shelf life

Unlike gasoline which you cannot store for longer periods without stabilizers, propane can be stored for a longer period without having to incur any costs for buying stabilizers. For proper long storage of propane, you have to ensure that the storage tank is clean and in good condition.

It is easier and cheap to maintain propane-powered generators

Since propane burns clean, it doesn’t leave suit or carbon deposits on the exhaust, fuel lines, and other parts. Diesel and gasoline leave such deposits in the mentioned areas making it is relatively hard to maintain gasoline or diesel-powered generators.

Propane gas is readily available

You can refill or exchange your propane tank in the nearest gasoline station. During emergencies such as natural disasters that cause interruption of electricity supply, you cannot get gasoline. This is because gasoline pumps require the presence of electricity to work.

Propane is a safe fuel source

In case of any leakage, propane will not harm the environment, unlike gasoline or diesel.

Frequently Asked Questions

How long will a generator run on a 40 lb tank?

It depends on the load and size of the generator. Ideally, a 3,500-watt generator running on a 50% load can run for about 20 hours.

Does a generator run longer on propane or gas?

How Much Propane Does a Generator Use This will depend on the wattage load on the generator. On average, gas tends to offer generators more runtime compared to propane. It’s because gas offers more BTU per gallon of fuel compared to propane.

What are the disadvantages of propane?

Propane is a clean energy source; however, it has several disadvantages, including:

  • It delivers a low BTU per gallon of fuel compared to gas.
  • It is highly flammable, making it dangerous should it leak into the open air.

What is better, diesel or propane generator?

If your concern is environmental safety, propane generators are the best propane burns clean. However, if your concern is fuel efficiency and high output power, diesel generators are good. Gas generators are affordable compared to propane and diesel models.

How many pounds of propane are in a 20-pound tank?

A 20-pound tank can hold 20 pounds of propane. This amount of propane translates to 4.7 gallons.

How do you know you are low on propane?

Pour a cup of boiling water on the side of the tank and start feeling the tank. The point that feels hot is empty, while the point that feels cool is filled with propane. If the cool feeling is on the lower side of the tank, then you are running low on propane.

How much does it cost to fill a 20 lb propane tank?

The cost of filling a 20-pound propane tank depends on the refilling rate per gallon. It will cost you $3 to $4 per gallon. And since a 20-pound propane tank holds about 4.7 gallons, it will cost you $14 to $20 to refill it.

Can I use a 15 lb propane tank instead of 20?

Yes. A 15-pound propane tank means you will be using 3.5 gallons of propane instead of 4.7 gallons.

How much does it cost to fill a 30 lb propane tank?

A 30-pound propane tank can hold approximately 7 gallons of propane. With the rate of $3 to $4 per gallon, it will cost you between $21 to $30 to fill a 30-pound propane tank.

How much does it cost to fill a 20 lb propane tank at Costco?

It will cost you about $9.96 to refill a 20 lb propane tank in Costco. The prices are significantly low compared to other areas.

Is it bad to run a propane tank empty?

Yes, running a propane gas can be dangerous. In worse scenarios, it can cause explosions and fire.

Does propane smell when the tank is low?

Yes, It is easy to sense a strong odor of propane when the tank is low. Odor settles at the bottom, and when the gas runs low, the odor becomes active.

Can empty propane tanks explode?

No. Propane tanks cannot explode by themselves. It may take you a lot of effort to make a propane tank explode.

At what percentage should you fill your propane tank?

As a safety measure, propane tanks should be filled up to 80% level. The 20% allowance is to allow for expansion of propane when heat is added.

How long will a 100-gallon propane tank run a generator?

A 100-gallon propane tank can power a 7,000-watt generator for 66 hours, while a 12,000-watt model can run for 36 hours. In both circumstances, the generators are operating 25-75% load.

How long will a generator run on a 20 lb tank of propane?

On average, a generator can consume two to three pounds of propane hourly. Therefore, a 20-pound propane tank can power the generator for about 5 hours.

How much propane does a generator use per hour?

On average, propane-powered generators can consume 2-3 gallons per hour. However, this will also depend on the efficiency of the generator and its watt-load.

How much propane does a generator use in a day?

Depending on your generator and the load, a generator consumes about 2-3 gallons per hour. Running such a generator for 12 hours will consume between 24-36 gallons.

How long will a 5-gallon propane tank run a generator?

A generator’s load and model play a major role in determining how long the generator will run on any amount of propane. Particular models can run for 8 hours when powered by a 5-gallon propane tank.

Is it cheaper to run a generator on propane or gas?

Gasoline generators are affordable to buy. Unless you reside in an area where propane is readily available than gas, it is cheaper to buy gasoline than propane.

Is it better to run a generator on propane or gas?

Running your generator on propane will deliver lower BTU per gallon of fuel than when you are running it on gas. Even so, propane burns clean and is friendly to the environment.


The amount of propane gas a generator consumes depends on several factors, including load and the generator’s efficiency. On average, most propane-powered generators use 2-3 gallons of propane per hour. Learn how to calculate a generator’s propane consumption before buying one.


About Steve Stuart

Steve Stuart is an electrical engineer who developed interest on generators during his school years. After school, he became a generator enthusiast. This is after encountering power supply problems at the area of residence where he lived. Power would be on and off and so food would go bad and the room heater would go off especially during winter. After trying the different generator brands for several years, Steve now provides information on the available brands and products in the market today. Based on his experience, he gives the do’s and the don’ts when it comes to generator use.

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