What is the Tri Fuel Selector Switch?

Natural Gas and Propane (LPG) are pressurized differently. Natural Gas is very low pressure, typically between 3-8 WC.  Propane (LPG) is high pressure, typically 10 psi. The regulator installed on our Propane Hoses reduces the pressure from 10 psi to 11 WC, which is still higher pressure than typical Natural Gas pressure. On a Standard Tri Fuel Setup, changing between Natural Gas and Propane (LPG) would require a slight adjustment to the load block to account for the difference in pressure between these two fuels. For those who plan on switching between Natural Gas and Propane (LPG) frequently or for those who want the convenience of simply using a switch to change between fuels without the need for any adjustments, the Tri Fuel Selector Switch is the perfect option.

Natural Gas/Propane (LPG) vs Gasoline

Natural Gas & LPG are dependable in a crisis situation  Gasoline is an undependable commodity in a crisis situation
Propane and Natural gas burns clean = longer engine life  Gasoline leaves carburetors and air filters filthy = shorter engine life
Propane and natural gas powered engines are environmental friendly  Gasoline generators produce harmful emissions into the environment
Longer, uninterrupted run times  Interrupted run times means you must refill all day and night
Connect to your natural gas pipe line or swap out LPG tanks  Wait on long lines IF the gas stations have gasoline available
No need to store Natural Gas, an unlimited supply is always available  Gasoline is dangerous to store in large quantities
Propane can be stored for years  Gasoline has a very limited shelf life
Quieter engine noise level  Louder engine noise level
There are no road taxes on propane or natural gas  Pay road tax on gasoline to run your generator


Fuel consumption in BTUs per hour of common appliances

Appliance Demand in BTU/hour
Barbeque (residential) 40,000
Boiler 140,000
Domestic Clothes Dryer 35,000
Domestic Gas Range 65,000
Domestic Recessed Oven Section 25,000
Fireplace Gas Log 80,000
Gas Refrigerator 3,000
Water Heater, 30-40 Gallon Tank 35,000
Water Heater, 50 Gallon Tank 50,000


Use this chart to estimate your fuel supply by pipe length



Propane (LPG) Tank Specifications

Tank Size 20 lbs 30 lbs 40 lbs 100 lbs
Capacity 4.7 gal 7.1 gal 9.4 gal 23.6 gal
Weight (empty) 18 lbs 24 lbs 29 lbs 68 lbs
Weight (full)  38 lbs 54 lbs 70 lbs 170 lbs
Overall Height 18 inches 24 inches 29 inches 48 inches
Diameter 12.5 inches 12.5 inches 12.5 inches 14.5 inches
BTU Capacity 430,270 649,980 860,542 2,160,509


Use this chart to estimate the fuel consumption by generator size

Generator Size Natural Gas
(BTU per hour)
Propane (LPG)
(Gallons per hour)
7000 Watts 135,000 0.57
10,000 Watts 177,000 0.66
13,000 Watts 200,000 1.0
16,000 Watts 230,000 1.19



The Relative Efficiency of Gasoline, Natural Gas, and

Propane Fuels For Back-Up Generators

By Bruce Dishongh

When purchasing a generator as a back-up power supply for your home, one thing to consider is which type of fuel you will be using. While there are several other important factors when buying a generator, this article is only concerned with the method of comparing the relative efficiency between gasoline, natural gas and propane.

The first thing to understand is the equivalent ratio of energy output for the three fuels as expressed in BTUs, the commonly used unit of energy. The following table will demonstrate:

· Gasoline 1 gallon = 125,000 BTUs
· Natural Gas 1 CCF = 100,015 BTUs (CCF=100 cubic feet)
· Propane 1 gallon = 91,700 BTUs

You can see from above that 1 gallon of gasoline is more efficient than 100 cubic feet of natural gas or 1 gallon or propane. In fact, the ratio is approximately:

· 1 gasoline = 1.25 CCF natural gas = 1.36 gallons propane

In other words, you would need 1.36 gallons of propane to produce the equivalent BTUs of 1 gallon of gasoline; or, 1.25 CCF of natural gas.

As a practical example let’s say that gasoline is currently $3.89 a gallon, natural gas $.60 per CCF (Keyspan New York, June 2013), and propane $2.39 a gallon (these are today’s prices where I live). Next, my generator uses 16 gallons of gasoline a day if run continuously for 24 hours. Therefore, for one day’s usage I need:

· 16 gallons of gasoline, or
· 16 x 1.25 CCF of gas, or
· 16 x 1.36 gallons of propane
· 16 gallons of gasoline, or
· 20 CCF of gas, or
· 21.76 gallons of propane

If we then enter the prices:

· ($3.89) x (10) for gasoline; ($.60) x (20) for natural gas; or, ($2.39) x (21.76) for propane
The cost for running the generator 24 hours is:
· $62.24 for gasoline; $12.00 for natural gas; or, $52.00 for propane

As you can see, once you know the relative efficiency of the three fuels you can just plug in the current prices of the fuels to calculate the daily cost of running your generator for each fuel. However, in the case of propane, the cost per gallon can vary widely depending on the number of gallons purchased.

If you are thinking of buying a generator it is best to consider more than just the initial purchase price. If you will be using it for extended periods of time it could be cheaper in the long run to buy a generator capable of running on alternative fuels.

Propane approximations
1 gallon = 91,500 BTU
1 cubic foot = 2,500 BTU
1 pound = 21,500 BTU
4.24 lbs = 1 gallon
36.39 cubic feet = 1 gallon