Out of all the modern backup power sources, generators are still everyone’s first choice. Not only can they run on a wide range of available fuels, but a portable generator can also power all the required devices simultaneously.
So, be it your refrigerator, heater, air conditioner, TV set, lamp, etc., you need not compromise on anything!
The only requirement is sufficient propane (or any fuel) on standby.
But how much propane do I need? How many gallons of propane does a generator use in a day?
A typical propanepowered generator will consume roughly 23 gallons per hour. Depending on your tank’s capacity and hours of usage, you can calculate the approx. propane requirement for the day, week, or month.
Read on as I answer all these questions in detail.
How Much Propane Does A Generator Use – Entire Math
Table Of Contents
Let’s now calculate how much propane a generator uses in an hour or day.
Note: All the following calculations and figures aren’t exact but approximate. An example is also discussed to calculate gallons of propane required by a 20kWh generator.
Some basic figures:
 Liquid propane weighs 4.2 lbs/pounds per gallon
 The fuel value of propane is 91,500 BTU
 1 HP of mechanical energy requires 10,000 BTU of fuel in an hour
We’ll use the above figures in the following calculations.
 Find out how much horsepower you need to run your electrical appliance.
Formula: Horsepower = (Watts/ 1000)*2
 Represent the above value in horsepower in terms of BTU.
Formula: BTU = Horsepower*10,000 (in 1 hour)
 Calculate the gallons of propane required.
Formula: BTU/91,500
Consider this example.
Suppose the generator capacity is 20kWh. In horsepower, it’d be 40 HP, as per the above formula. In BTU, it’d translate to 400,000 BTU.
To calculate the gallons of propane, you need to divide this 400,000 BTU by the current fuel value of propane, i.e., 91,500 BTU. Or 4.37 gallons.
So, 4.37 gallons of propane will be required to power a 20kWh generator.
Note: A 20pound propane tank contains 4.6 gallons of propane.
As you can see, a 20pound tank has an insufficient amount of propane to power your house for the whole day. Thus, I suggest keeping enough spare propane handy during outages.
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Factors That Affect How Much Propane A Generator Will Use In A Day
Now that we’ve calculated how much propane a generator uses in a day, it’s important to know what factors govern its daily consumption.
 Size Of Your Property
The bigger your property, the more propane your generator will use to power it during outages. This is because the generator will need to power up more devices than usual over a large area—for example, heaters in winter.
 Power Requirements Of Appliances
The power your electrical appliances use also influences the gallons of propane you’d require to power them up.
For example, a typical home refrigerator uses 350780 watts of power. Talking about a dehumidifier, a portable model is typically rated 3050 watts. If it’s a wholehouse dehumidifier, it’ll use an average of 250 watts per hour.
So, the power consumption of your electrical devices is also important when calculating how many gallons of propane your generator will use.
 Power Generating Capacity Of Your Generator
The next factor is the powergenerating capacity of your generator.
An average American home consumes 10,715 kilowatthours (kWh) in a year. Even if you lose power 10% of the time in a year, it translates to 1071.5 kWh, which is generated by approx. 535.75 horsepower.
As one horsepower consumes 10,000 BTUs of mechanical energy, it’ll require over 5,37,500 BTUs or 58 gallons of propane to power your home for just 10% of the time in a year.
 Number Of Hours Without Power
A generator of 20kW capacity uses anything between 23 gallons of propane per hour (again, an estimate). Thus, the more hours you spend without power and on the generator, the more gallons of propane are required.
Note: Other factors include your generator’s efficiency, tank capacity, outside conditions (winter/summer), budget, etc.
Related: Best Whole House Generator – 5 top Picks For All House Sizes
Why Should You Run A Generator On Propane?
Generators run on various fuels, for example, natural gas, gasoline, diesel, propane, etc. Among all these, efficiently burning and “cleaner” propane is a widely used fuel, be it for commercial or domestic generators.
Some of the critical benefits of using propane as fuel are as follows.
 Propane Is Readily Available
One of the main advantages of a propanepowered generator is easy access to propane. Unlike diesel or gas, which can only be refueled from fuel stations, you can store propane at your home in cylinders or tanks for quick access as the fuel runs out.
Thus, no rushing to the refueling stations!
 It’s A “Cleaner Fuel”
Besides being a nontoxic fuel, propane is also a great choice to reduce your environmental carbon footprint. It’s listed as a “cleaner fuel” in the 1970 Clean Air Act and Energy Policy.
Propane has:
 20% less nitrogen
 Up to 20% less greenhouse gas emissions
 60% less carbon monoxide (CM)
Note: You can also install propane tanks underground in your backyard without worrying about any soil contamination.
 Propane Is Cheap
Who doesn’t want to save a few bucks when it’s possible?
As 1 cubic foot of propane encompasses 2,516 BTUs, it’s more than 2x what natural gas, another popular fuel, offers. FYI, 1 cubic foot of natural gas has 1,030 BTUs.
Hence, propane produces more than 2x the energy of natural gas, thus cutting fuel costs.
 Propane Is Odorless
If you just hate the awful smell of gasoline, propane is for you as it’s odorless. Plus, it evaporates quickly.
Note: Since liquid propane can leak if not stored properly, some companies add ethyl mercaptan to produce a faint odor to understand the exact point of a leak from the cylinder or tank.
 Propane Has An Indefinite Shelf Life
Did you know that propane can last for an indefinite period? Thus, it’s the most stable and resilientfriendly fuel around.
In other words, propane doesn’t lose its potency over time and degrade. FYI, the shelf life of diesel is 1 year, and for gasoline, it’s just 36 months.
Related: Propane vs Gas Generator: Which is Right For You?
How Much Propane Does A Generator Use FAQs

How Much Propane Does An 18kw Generator Use?
Ans: An 18kw generation would use up to 3.9 gallons of propane per hour. Multiply this by the total number of hours the generator would run for in the day for an overall estimate.

How Much Propane Does A 14kw Generator Use Per Hour?
Ans: A 14kw generator will use approximately 3 gallons of propane per hour.

How Much Propane Does A WholeHouse Generator Use Per Hour?
Ans: The quantity of propane a wholehouse generator will use per hour will depend on factors such as the number of hours, wattage, number & nature of appliances run, etc.
Once you have all this data, use the equation for calculation.

How Much Propane Does A 12000Watt Generator Use?
Ans: A 12 000watt generator will use up to 2.42.5 gallons of propane per hour.
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Conclusion
So, here you go. Inexpensive, cleaner, and accessible, Propane is the best choice to power your generator and home. However, it’s always wise to have a rough figure of how many gallons of propane you’d require to avoid any lastminute hiccups.
To help you out, I’ve done the math above and figured out the gallons required per hour.
You just need to multiply it by the total number of hours the generator will run, and you’re ready to go!