Are Propane Furnaces and Natural Gas Furnaces the Same?

There are still many rural areas that don’t have natural gas service to their area.  If you are considering moving to one of these areas, you may be asking, “Are propane furnaces and natural gas furnaces the same?”  Perhaps you already live in a rural area and now natural gas is available.  You may be considering tying into the natural gas line or staying with propane.  This gas furnaces guide will help to answer your questions.

Are Gas Furnaces and Propane Furnaces the Same?

The answer is yes, with a slight modification.  Most furnaces are manufactured for natural gas but they can be converted for use with propane fairly easily.  If you plan ahead, you can order your furnace outfitted for propane, but most are switched from natural gas use to propane use when they are installed by a furnace contractor.

The switch from using natural gas to propane is accomplished with a conversion kit.  It includes a new orifice that assists in the transition of the liquid into a gas so that it can be efficiently burned in the furnace burner.  In most cases, the orifice is all that needs to be changed.  In some furnaces, the entire burner must be switched, but this is rare.  Check before you choose a furnace to make sure it can be easily converted to propane use.  Most conversion kits cost less than $75 and take about 30 minutes or less for an professional furnace technician to install.

Does Natural Gas or Propane Heat More Efficiently?

Propane heats more efficiently than natural gas, but depending on the prices for both in your area, that doesn’t necessarily mean it will heat less expensively.  If you have a gas bill, it will show your natural gas usage in cubic feet of gas.  If you have propane delivered, it will be charged to you by gallons.  Propane and natural gas compare this way:

1 gallon of liquid propane = 36 cubic feet of propane gas.

1 cubic foot of propane contains 2,515 Btu of heat.

1 cubic foot of natural gas contains 1,030 Btu of heat.

In other words, propane contains 2.44 times the usable energy that natural gas does.

An 80,000 Btu natural gas furnace will use 77.6 cubic feet of natural gas per hour (80,000 divided by 1,030).

An 80,000 Btu propane furnace will us 31.8 cubic feet of propane per hour (80,000 divided by 2,515).

Do Propane Furnaces Cost Less to Operate than Gas Furnaces?

Not necessarily.  It depends on the relative costs of propane and natural gas in your area.  Your utility company will give you the price of natural gas in cubic feet.  For the price of propane in cubic feet, divide the price per gallon by 36 to determine the price per cubic foot. Then you can compare apples to apples.


In most parts of the country, natural gas is a cheaper way to heat than propane.  This remains true even when taking into account the greater heating value of propane when compared to natural gas.  Propane is simply that much more expensive currently.  It is more costly to refine than natural gas and there are fewer plants refining propane.  These factors make it more expensive overall.

As far as the environment goes, both propane and natural gas are labeled as alternative fuels.  They both burn very clean compared to fuels like gasoline or coal.

In terms of home comfort, both natural gas and propane do an outstanding job of heating.  You’ll notice very little difference between the two.

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