How to Compare Natural Gas & Propane Gas Costs

Updated April 17, 2017

The comparison of propane versus natural gas for residential fuel supply is a popular topic with homeowners trying to reduce their heating costs. Natural gas is made up of several gases including propane, and mostly consists of methane. Propane is a hydrocarbon separated from the other gases at gas processing facilities. It is stored as a liquid. Natural gas is stored as liquefied natural gas (LNG), compressed natural gas (CNG) or in its uncompressed form.

Consider that the efficiency of natural gas and propane burners have a huge impact on the real cost you will pay. Some newer burners are more than 90 per cent efficient, while others may operate at 75 per cent or less. This can reduce the overall heating efficiency to only 50 per cent to 60 per cent. Control burner efficiency by adjusting the air-to-fuel ratio and the fuel injection system for efficient combustion. Otherwise, soot will build up on the heat exchanger and insulate it, causing more heat to go up the chimney.

Estimate how many BTUs your house will consume in one winter. (One "British Thermal Unit" will raise the temperature of 1 pound of water 1 degree Fahrenheit). Examine last winter's heating bills or call your energy company to help you estimate your home's heating needs. You'll need to know the approximate square footage and have some idea of the quality of your insulation to help them with the estimate. Once you know the estimated number of BTUs your home needs, you can compare propane versus natural gas costs. Call your local propane and natural gas supplier for their prices based on the estimate of BTUs you consume.

Factor in the monthly facilities charge for natural gas in order to arrive at a total cost of utility service. There may also be a monthly tank charge levied by your propane dealer. Note also that it costs about £48 per year to lease a propane tank.

Look for energy comparison calculators on the Internet to make your own estimate or to confirm information you get from your local propane and gas company suppliers. There are several charts and calculators comparing propane to natural gas costs. You will notice that they convert the current propane price per gallon by multiplying by 1.09 to arrive at the comparable price of natural gas in therms. The reason they do that is that the heat content for propane is 91,500 BTU per gallon whereas the heat content for natural gas is100,000 BTU per therm. So 100,000/91,500 = 1.09.)


Talk to neighbours and friends about their experiences with natural gas versus propane. Sometimes figures on paper don't give you a true picture of all the considerations.


If you use natural gas primarily for heating three to five months of the year, remember that you'll still get a bill from the company every month for the meter, taxes, and possibly other minor charges.

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About the Author

Lorena Cassady has written professionally since 1982. She was an instructor and mentor teacher for a Bachelor of Arts in management program and has administered a home-health agency. She has been published in "Traveler's Tales" and holds a Master of Arts in English and creative writing from San Francisco State University. Cassady is bilingual.