Propane vs Heating Oil: Which Home Heating Fuel Costs Less

Choosing between propane and heating oil usually comes down to one question: which one costs less to heat your home? The short answer is that it depends — not just on the price per gallon, but on how much heat each gallon produces, how efficient your furnace or boiler is, and what you pay for storage, delivery, and maintenance.

This guide breaks down both fuels in plain terms. You’ll learn how each one works, how to compare them fairly using a simple cost-per-heat calculation, and which factors tend to tip the balance in one direction or the other.

The Short Answer

Heating oil delivers more heat per gallon than propane, so it often looks cheaper on a per-gallon basis — but that comparison can be misleading. Propane systems frequently run at higher efficiency, and propane prices tend to swing differently than oil prices through the year.

In practice, either fuel can be the cheaper option depending on local pricing, your equipment, and how much fuel you use each winter. The only reliable answer is to calculate your own cost per unit of usable heat.

How Each Fuel Works

Propane

Propane is a liquefied petroleum gas stored under pressure in a tank, usually outside the home. It feeds a furnace, boiler, or space heater, and can also power water heaters, cooking ranges, and backup generators. Because it’s a gas, it burns cleanly and doesn’t leave the same residue in the system that liquid fuels can.

Heating Oil

Heating oil is a liquid fuel stored in a tank, often in a basement or outdoors. It is pumped to a burner, where it’s atomized and ignited to create heat. Oil systems typically require annual cleaning and filter changes, but the equipment itself is known for a long service life.

Comparing Heat Content and Efficiency

The two fuels aren’t measured the same way in terms of usable heat. A gallon of heating oil contains roughly 138,000 to 139,000 BTU, while a gallon of propane contains about 91,500 BTU. That means oil carries noticeably more energy per gallon.

Efficiency narrows the gap. Modern propane furnaces can reach 90% to 98% efficiency, while many oil systems run between 80% and 90%, though high-efficiency oil models can approach 95%.

Factor	Propane	Heating Oil
Energy per gallon	About 91,500 BTU	About 138,500 BTU
Typical equipment efficiency	80%–98% AFUE	80%–95% AFUE
Storage	Pressurized tank, above or below ground	Liquid tank, indoors or outdoors
Equipment lifespan	Often 15–20 years	Often 20–30 years
Other household uses	Cooking, water heating, generators	Mainly heating and hot water

How to Compare Costs Accurately

Price per gallon tells you very little on its own. To compare fairly, convert both fuels to cost per million BTU of delivered heat.

Find the current price per gallon for each fuel in your area.
Divide that price by the fuel’s heat content. Use 91,500 BTU for propane and 138,500 BTU for heating oil.
Multiply by 1,000,000 to get the raw cost per million BTU.
Divide by your system’s efficiency as a decimal. For example, 92% becomes 0.92.
Compare the two results. The lower number is the cheaper fuel for your setup.

The formula looks like this: (price per gallon ÷ BTU per gallon) × 1,000,000 ÷ efficiency.

A Worked Example

Suppose propane costs $2.50 per gallon and your furnace is 92% efficient. The calculation is (2.50 ÷ 91,500) × 1,000,000 ÷ 0.92, which comes to roughly $29.70 per million BTU.

Now suppose heating oil costs $3.80 per gallon and your boiler is 85% efficient. The calculation is (3.80 ÷ 138,500) × 1,000,000 ÷ 0.85, which comes to about $32.30 per million BTU. In this example, propane is the less expensive option.

These are illustrative numbers only. Plug in current local prices and your own equipment’s efficiency rating to get a meaningful result, and recheck it before each heating season.

Costs Beyond the Price Per Gallon

Fuel price is only part of the total cost of ownership. These extras can shift the balance significantly:

Tank ownership or rental: Some suppliers lease tanks for a monthly or annual fee; others require you to buy one outright.
Delivery charges: Small or emergency deliveries often carry a premium. Automatic delivery plans can reduce this.
Maintenance: Oil systems generally need annual cleaning, nozzle and filter replacement, and more frequent service calls. Propane systems typically need less routine attention.
Equipment replacement: High-efficiency units cost more upfront but lower your cost per unit of heat over time.
Conversion expenses: Switching fuels usually means new equipment, a new tank, and possibly new venting or piping.
Insurance and inspection: Some policies treat one type of tank differently than the other, which can affect premiums.

Price Stability and Buying Patterns

Both fuels are tied to broader energy markets, so prices move with seasonal demand and supply conditions. Heating oil prices tend to rise in winter, when demand peaks. Propane also rises in winter but is used for many non-heating purposes year-round, which can smooth out or complicate its pricing.

One practical advantage of oil is that it can be bought in bulk and stored for long periods without losing quality. Propane tanks can also be filled in advance during lower-price periods, which is a common way to reduce the average cost per gallon.

Practical Differences That Affect Your Bill

How well your home holds heat matters as much as the fuel itself. A well-insulated home with sealed ducts and a properly sized system will cost less to run on either fuel. Oversized equipment, leaky ductwork, and unsealed attics waste money regardless of what’s burning in the furnace.

Propane has one additional advantage: because it can power multiple appliances, a single tank can cover heating, hot water, cooking, and even a backup generator. That consolidation can reduce separate service fees.

Which Fuel Usually Costs Less?

There is no universal winner. In general terms:

Propane tends to win when propane prices are moderate, when you have a high-efficiency furnace, and when you can use one tank for multiple appliances.
Heating oil tends to win when oil prices are low, when you have a modern high-efficiency boiler, and when your tank and equipment are already paid for.

For most households, the deciding factor is the gap between local propane and oil prices combined with the efficiency of the existing equipment. A difference of a few cents per gallon can reverse the outcome.

How to Lower Heating Costs With Either Fuel

Service the system annually. A clean, tuned burner uses less fuel.
Buy before peak season if your supplier offers preseason pricing or lock-in contracts.
Sign up for automatic delivery to avoid premium emergency fills.
Seal and insulate attics, basements, and ductwork.
Install a programmable thermostat and lower the temperature while sleeping or away.
Upgrade when it makes sense. Replacing an old furnace with a high-efficiency model often pays back within a few seasons.

Frequently Asked Questions

Is propane cheaper than heating oil?

Not always. Propane usually costs less per gallon, but oil contains more heat per gallon. Whether propane is cheaper overall depends on current prices and the efficiency of each system.

Does propane heat a home as well as oil?

Yes. Both fuels produce comfortable, consistent heat when the equipment is correctly sized and maintained. The difference is how much fuel each system consumes, not how warm the house feels.

Which fuel is safer?

Both are widely used and safe when stored and maintained properly. Propane is flammable and heavier than air, while heating oil is combustible rather than easily ignited. Each requires proper installation and regular inspection.

Can I switch from one fuel to the other?

Yes, but it requires new heating equipment, a new tank, and sometimes changes to venting or piping. Because of the upfront cost, switching usually makes sense only when the existing system is due for replacement anyway.

How often should tanks be checked?

An annual inspection is a reasonable standard for both fuel types. Look for leaks, corrosion, or damage, and have the tank professionally serviced if anything seems unusual.

The Bottom Line

Neither propane nor heating oil is automatically the cheaper choice. Heating oil packs more energy per gallon, while propane systems often run more efficiently and can serve more appliances from one tank. The most accurate way to decide is to calculate cost per million BTU using current prices and your equipment’s efficiency rating.

If you’re comparing other home systems and appliances, explore more practical guides on heating, cooling, and household budgeting to keep every part of your home running efficiently.