If you’re like most people, you probably don’t give much thought to your home’s backup power until the electricity goes out. Then, you start to wonder how long your generator will run on a tank of propane. The answer to that question depends on a few factors, including the size of your generator and the load required.

## How much propane does a backup generator use?

**Expect a propane-powered generator to use between 2-4 gallons each hour. ** You can run your house for a week with a 500-gallon tank. For two weeks, a 1,000-gallon tank may be used.

A typical 20 kW propane backup generator will consume around 2-4 gallons of propane per hour, depending on what you’re powering and the load (2 gallons at half load, and 4 gallons at full load continuous). At this consumption rate it would take around six to seven days to use up 500 gallons of propane.

## How Long Will a Propane Tank Last When Running a Generator?

How many hours will a propane tank run a generator?

**There is a simple equation to figure out how long a tank of propane will last when running a backup generator full-time**:

**How long a propane tank will last = tank capacity / generator consumption rate**

### Gallons of Propane

We can use this equation by considering the gallons in the tank vs. the generator’s consumption rate in gallons per hour.

**How long a propane tank will last = tank capacity in gallons / generator consumption rate in gallons per hour**

For example, if you have a tank with 500 gallons in it and your backup generator uses 3.4 gallons per hour on average, then your tank will last 500 / 3.4 = 147 hours or 6.1 days.

However, for safety reasons tanks are only filled to 80% capacity, so a 500 gallon propane tank would only have 400 gallons in it to burn. This would reduce your generator run time from 147 hours to 117.6 hours or 4.9 days. That’s a substantial difference from 6.1 days.

### Pounds of Propane

We can also look at this in terms of pounds of propane as follows:

**1 pound of propane = 0.236 gallons**

**How long a propane tank will last = tank capacity in pounds / generator consumption rate in pounds per hour**

For example, a tank with 500 gallons of propane contains about 500/0.236 = 2118.6 pounds of propane. The same backup generator as above that uses a n average of 3.4 gallons per hour would consume 14.4 gallons of propane per hour. Your tank will last 2118.6 / 14.4 = 147 hours or 6.1 days.

You could also do the calculations in liters and get the same results.

**These equations are demonstrated using an average consumption rate. **To be more accurate, you would probably want to **calculate the highest and lowest **amount of time your propane will last, using your lowest and highest consumption rates. This will give you a better idea of your time capacity should you need to run your backup generator at full tilt, and how much more time you could gain if you backed your generator load down so it only used half the propane per hour.

#### Highly-rated portable backup generators to check out:

Westinghouse 4650 Watt Gas / Propane Dual Fuel Portable Backup Generator, RV Ready 30A Outlet

DuroMax XP13000EH 13 kW Gas / Propane Dual Fuel Portable Backup Generator

WEN DF475T 4750 Watt Gas / Propane Dual Fuel 120V/240V Portable Backup Generator

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## Time Estimates in Gallons of Propane

As a rule of thumb, here are some **estimates of generator run time by gallons of propane**. These estimates are for a typical 15-20 kW backup generator consuming 2-4 gallons (8.47-16.95 pounds) per hour.

### How long will a 1000-gallon propane tank run a generator?

This size propane tank is quite large. A 1000-gallon tank would normally be filled to a maximum of 800 gallons. If your backup generator uses 2-4 gallons per hour you’d get a high of 400 hours (16.7 days) and a low of 200 hours (8.3 days) out of it.

### How long will 500 gallons of propane last?

A 500-gallon propane tank with 400 gallons in it will allow a maximum of 200 hours (8.3 days) and a minimum of 100 hours (4.1 days) of backup generator run time. Again, this assumes 2-4 gallons per hour consumption rate.

### How long will 250 gallons of propane last?

A 250-gallon tank filled with 200 gallons of propane will allow a maximum of 100 hours (4.1 days) and a minimum of 50 hours (2.1 days) of time for a running backup generator, assuming 2-4 gallons per hour of consumption.

### How long does a 120-gallon propane tank last for a generator?

A 120-gallon propane tank will be filled to 96 gallons. A backup generator consuming 2-4 gallons per hour will run for a maximum of 48 hours (2 days) at half load and only 24 hours (1 day) at full load.

### How long will a Generac generator run on 250 gallons of propane?

Propane tanks typically range in size from 250 to 1,000 gallons. 250 gallons is on the low end of the range, holding only 200 gallons of propane when filled to 80%. A 22 kW Generac generator uses about 2 to 3 gallons of propane every hour for normal household loads, on average. So an electrical outage of between 2.77 and 4.16 days can be handled with a 250-gallon propane tank at this estimated 2-3 gph rate.

## Time Estimates in Pounds of Propane

Here are **estimates of generator run time by pounds of propane**. These estimates are for a typical 15-20 kW backup generator consuming 2-4 gallons (8.47-16.95 pounds) per hour.

### How long will 5 gallons of propane run a generator?

5 gallons of propane will run a whole house backup generator for about 1.25 to 2.5 hours.

### How long will a 10-gallon propane tank last with a generator?

10 gallons of propane will run a 15-20 kW backup generator for about 2.5 to 5 hours.

### How long will a 20-pound propane tank last running a generator?

A 20-pound propane tank will last between 1.77 and 3.54 hours for a typical 15-20 kW home backup generator. This small tank is not very useful in an emergency, even with a smaller generator. Even if you had a lot of tanks you would need to change them constantly to keep your backup generator running.

### How long will a generator run on 30 lbs of propane?

A 30-pound propane tank will last between 1.17 and 2.36 hours for a normal 15-20 kW home backup generator. A 30-pound tank is still too small to run a house backup generator for emergencies.

### How long will a home backup generator run on 1000 lbs of propane?

A 1000-lb propane tank is much more suited for emergency backup situations to keep your house power and appliances going. This size tank will last between 59 (2.5 days) and 118 hours (4.9 days) for a 15-20 kW home backup generator using 8.47 to 16.95 pounds of propane per hour.

## Related Questions And Answers

### Are propane generators good?

Propane generators are ecologically beneficial. Because they emit fewer pollutants than gasoline and diesel, propane is regarded as a clean-burning fuel. Both the environment and your generator will benefit from this. Gasoline creates twice as much carbon monoxide per unit volume as propane.

### How much propane does a whole house generator use per hour?

A typical 15-20 kW whole house generator will use about 2-3 gallons of propane per hour on average. At peak loads, the generator may consume up to 4 gallons per hour, but this will normally be offset by much lower consumption at off-peak hours.

### How Much Propane Does a Backup Generator Use?

The amount of propane used by a generator varies. This video can give more information:

### How much propane does a 16kw Generac generator use per hour?

Each hour, this sized generator uses the equivalent of around 2.4 gallons of propane.

### How much does it cost to run a Generac generator on propane?

Depending on the price of natural gas, running the unit in workout mode should not cost more than $5 or $10 a month. Under 50% load, you should expect to spend $20-$40/day for gas during a power outage.

### How long will a Firman generator run on 5 gallons of propane?

This generator will run for more than five and a half hours.

### How many gallons does a 20 lb propane tank hold?

A 20 lb propane tank holds about 4.66 liters or 1.23 gallons.

### How many gallons does a 200-pound propane tank hold?

It will hold a total of 46 gallons.

### How long will a 10 kW to 12 kW backup generator run on propane?

Smaller home backup generators in the 10-12 kW range use less propane than the typical 15-20 kW generators do. These generators typically consume 1.5 to 3 gallons of propane per hour. However, due to their smaller size they tend to run at a higher load for extended tim eto power the appliances in a single family home. So you’re safer assuming 3 gph propane consumption.

This means 200 gallons of propane (typical capacity for a 250-gallon tank) will run a 10-12 kW backup generator for 66.7 hours or 2.8 days at 3 gallons per hour.

### Do generators run longer on gas or propane?

If you’re worried about running out of fuel, propane is a better option since it lasts longer.

### How many gallons of propane does an average household use per month?

The amount of propane used on a monthly basis for two individuals is about ten to fifteen gallons per month. The normal use for propane in a home is the stove, barbecue and possibly the HVAC system.

### Is it better to bury a propane tank?

Underground propane tanks have the advantage of being temperature-controlled, which is their greatest strength. As a result of their sheltered location, they experience less harsh heat and cold. The propane in the tank may be affected by extreme temperatures, but since the tank is buried, it is protected from the elements.

## Conclusion

The amount of propane your backup generator will use depends on the size of the generator and its level of efficiency. Make sure to check the manufacturer’s specs for more information.

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