Are propane and natural gas the same thing?

No. Both are gaseous hydrocarbons used for heating, but they are different molecules. Natural gas is mostly methane (CH₄); propane is C₃H₈. Natural gas is delivered through a utility pipeline as a low-pressure gas. Propane is delivered as a pressurized liquid that vaporizes in your tank regulator on the way to the appliance.

Which has more energy, propane or natural gas?

Propane is more than twice as energy-dense by volume. A cubic foot of propane vapor contains about 2,500 BTU; a cubic foot of natural gas contains about 1,030 BTU. That means a propane appliance burns less than half the volume of a natural-gas appliance to deliver the same heat — which is why propane orifices and burner jets are smaller than natural-gas equivalents.

Can I use a natural-gas appliance on propane?

Only if it is converted with the manufacturer-supplied LP conversion kit, which swaps the burner orifices and adjusts the gas valve to handle propane's higher pressure and energy density. Many modern furnaces, water heaters, and ranges ship dual-fuel-rated; older appliances and some commercial equipment are field-converted by a licensed technician. Running an unconverted natural-gas appliance on propane creates an over-firing condition and is unsafe.

Is propane or natural gas cheaper?

It depends on your region and the time of year. Natural gas — when you have utility service — is almost always cheaper per BTU than delivered propane, because pipeline delivery has lower marginal cost than truck delivery. Propane wins in any home that does not have natural-gas service: extending a utility line is often $50–$200/foot in capital cost, which dwarfs years of fuel savings.

Can I switch a natural-gas home to propane?

Yes, but it is more common to go the other direction (propane → natural gas) when utility service becomes available. Switching from natural gas to propane requires installing a tank, the regulator and supply line, and converting every gas appliance with the appropriate LP conversion kit. The driver is usually a utility outage, a remote second home, or a desire for backup capacity behind the natural-gas service.

Propane vs. Natural Gas: Energy, Cost, and Equipment Differences

Propane and natural gas burn similarly but cost, deliver, and store differently. Compare BTUs per cubic foot, equipment compatibility, and which fuel fits which kind of home.

Propane and natural gas are both gaseous fuels used for heating, cooking, and water heating, but they are different products with different delivery models, energy contents, and economics. The choice between them is rarely a real choice — it is determined by whether your property has natural-gas utility service available at the curb. Where both are options, the numbers favor natural gas.

Side-by-side

Factor	Natural gas	Propane
Primary molecule	Methane (CH₄)	Propane (C₃H₈)
Delivery	Utility pipeline	Tank truck → on-site tank
Stored as	Pressurized pipe gas	Liquid in a pressurized tank
Energy content	~1,030 BTU / cubic foot	~2,500 BTU / cubic foot
Energy per gallon (liquid equivalent)	n/a	~91,500 BTU / gal
Burner orifice	Larger	Smaller
Service interruption	Rare; utility-managed	Tied to scheduled deliveries
Available in rural areas?	Often no	Yes
Typical delivered cost	Lower per BTU when available	Higher; truck delivery overhead

The energy-density difference is the most important practical fact. A propane appliance burns through less than half the volumetric flow of a natural-gas equivalent because each cubic foot of propane carries about 2.5× the heat. That difference is why every fuel-flexible appliance ships with two sets of orifices — one sized for natural gas, one for propane — and why an unconverted natural-gas appliance over-fires on propane and an unconverted propane appliance under-fires on natural gas.

Equipment compatibility

Most modern furnaces, water heaters, ranges, dryers, and boilers ship dual-fuel-rated: the same chassis is sold either factory-set for natural gas or with an LP conversion kit included for propane. NFPA 54 governs how the conversion is performed:

“Where appliances are converted from one type of gas to another, the conversion shall be performed using a manufacturer-authorized conversion kit and shall be made by a qualified agency.”
NFPA 54 / ANSI Z223.1, §5.21 (Conversion to a Different Fuel Gas — National Fuel Gas Code, 2024 ed.). View source

In practice that means a licensed installer using the manufacturer's LP kit swaps orifices, adjusts the gas-valve regulator output pressure, and verifies combustion analysis at startup.

Older equipment — pre-2000s gear, some commercial models — is built for one fuel only. Field-converting a single-fuel appliance is manufacturer-dependent: some publish a conversion procedure, others treat the appliance as not convertible.

Cost

When natural-gas service is available at the curb, natural gas is nearly always cheaper per delivered BTU than propane. The pipeline delivery model has lower marginal cost than truck delivery. The EIA publishes regional residential prices for both fuels; most regions show natural gas running roughly half the per-MMBTU cost of delivered propane.

When natural-gas service is not available, the comparison flips entirely:

Extending a utility line typically costs $50–$200/foot in capital,
paid by the homeowner.
A natural-gas service connection that requires a 500 ft extension
starts at $25,000.
Propane infrastructure (tank + regulator + supply line) for the same
home is in the $1,500–$5,000 range installed.

For any home outside utility-service range, propane is the answer that makes financial sense even if the per-BTU cost is higher.

Reliability and resilience

The two fuels have different failure modes:

Natural gas is utility-delivered. Service interruptions are rare
but, when they happen, affect entire neighborhoods at once and
require utility action to restore.
Propane is on-site storage. There is no utility to fail —
whatever is in your tank keeps running through any storm or grid
event — but you depend on your supplier's delivery cadence to refill
the tank.

For backup-power generators, propane is the dominant fuel specifically because of this property: an extended outage that takes down the grid also takes down the natural-gas compressor stations on a long timeline, while propane stored on-site keeps the generator running until the tank empties.

Which fits which home

Natural-gas service at the curb: take it. The long-run cost
advantage is real and the delivery model is hands-off.
Rural or off-grid: propane. The line-extension cost makes
utility natural gas a non-starter.
Mixed neighborhoods at the edge of utility service: get a
written quote from the utility for line extension, compare it to the
payback on switching to propane, and remember the utility rate is
regulated and you can't shop it among providers.

Use the directory to find local propane suppliers in your area — search by ZIP to see who delivers near you.

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Frequently asked questions

Are propane and natural gas the same thing?: No. Both are gaseous hydrocarbons used for heating, but they are different molecules. Natural gas is mostly methane (CH₄); propane is C₃H₈. Natural gas is delivered through a utility pipeline as a low-pressure gas. Propane is delivered as a pressurized liquid that vaporizes in your tank regulator on the way to the appliance.
Which has more energy, propane or natural gas?: Propane is more than twice as energy-dense by volume. A cubic foot of propane vapor contains about 2,500 BTU; a cubic foot of natural gas contains about 1,030 BTU. That means a propane appliance burns less than half the volume of a natural-gas appliance to deliver the same heat — which is why propane orifices and burner jets are smaller than natural-gas equivalents.
Can I use a natural-gas appliance on propane?: Only if it is converted with the manufacturer-supplied LP conversion kit, which swaps the burner orifices and adjusts the gas valve to handle propane's higher pressure and energy density. Many modern furnaces, water heaters, and ranges ship dual-fuel-rated; older appliances and some commercial equipment are field-converted by a licensed technician. Running an unconverted natural-gas appliance on propane creates an over-firing condition and is unsafe.
Is propane or natural gas cheaper?: It depends on your region and the time of year. Natural gas — when you have utility service — is almost always cheaper per BTU than delivered propane, because pipeline delivery has lower marginal cost than truck delivery. Propane wins in any home that does not have natural-gas service: extending a utility line is often $50–$200/foot in capital cost, which dwarfs years of fuel savings.
Can I switch a natural-gas home to propane?: Yes, but it is more common to go the other direction (propane → natural gas) when utility service becomes available. Switching from natural gas to propane requires installing a tank, the regulator and supply line, and converting every gas appliance with the appropriate LP conversion kit. The driver is usually a utility outage, a remote second home, or a desire for backup capacity behind the natural-gas service.