Oil vs. Propane Heating: Comparing Efficiency and Cost

In Massachusetts, heating oil delivers more heat per dollar than propane because a gallon of oil contains about 1.5 times the energy of a gallon of propane. Both often sell for nearly the same price per gallon. Propane wins on equipment efficiency, venting flexibility, and whole-home versatility, and it avoids supply-line rules that apply only to oil heat. The right answer depends on what you already have installed.

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Homeowners call us in October, compare two numbers from delivery tickets, and reach the wrong conclusion. Price per gallon is what every dealer advertises and what they tell you the least. In our 130+ years heating Central Massachusetts homes, the figure that predicts your winter bill is cost per unit of delivered heat.

Oil vs Propane Heating: Why Price Per Gallon Misleads

A BTU, or British thermal unit, is the amount of energy required to raise one pound of water by one degree Fahrenheit, and it is the unit used to compare fuels fairly. Standard conversion factors from the U.S. Energy Information Administration put a gallon of heating oil at about 138,500 BTU and a gallon of propane at about 91,500 BTU.

One gallon of oil carries the heat of about 1.5 gallons of propane, so a propane system burns roughly half as many gallons to maintain the same temperature. At last winter’s Massachusetts prices, oil at $3.10 per gallon costs about $22.38 per million BTU; propane at $3.17 costs about $34.64 per million BTU. That is roughly 55% more for the same delivered heat.

What Massachusetts Households Actually Spent Last Winter

The Massachusetts Department of Energy Resources surveys full-service dealers weekly and publishes the results so that you can check a dealer’s price against a state number. For the 2025/26 season, DOER projected heating oil to average $3.10 per gallon and propane to average $3.17 per gallon.

DOER estimated the average oil-heated household would spend about $1,103 on winter heat, compared with about $1,412 for the average propane-heated household. Despite near-identical per-gallon prices, the difference in the bill is roughly 28%.

Oil vs Propane Heating in Massachusetts: Cost, Efficiency, and Emissions

Comparison	Oil Heating	Propane
Energy per gallon	138,500 BTU	91,500 BTU
2025/26 MA average price	$3.10 a gallon	$3.17 a gallon
Fuel cost per million BTU	$22.38	$34.64
Projected MA household winter bill	$1,103	$1,412
Typical equipment AFUE	83 to 87%	80 to 98%
CO2 per million BTU	163.45 pounds	138.63 pounds
State supply line rules	Yes, Chapter 453	None

AFUE Ratings and Where They Stop Being Useful

Annual fuel utilization efficiency, or AFUE, is the percentage of fuel energy a heating system converts into usable heat across a season, with the rest lost up the flue. An 85% AFUE boiler turns 85 cents of every fuel dollar into heat.

Propane Reaches Higher on Paper

Propane burns cleanly enough for a condensing heat exchanger, a second exchanger that pulls extra heat from the exhaust by condensing water vapor. Condensing equipment starts at 90% AFUE and modern propane units reach the high 90s. Oil tops out in the mid-80s, because oil combustion products are harder on that exchanger.

Efficiency Does Not Erase the Fuel Gap

This is where homeowners overcorrect. A 95% propane boiler versus an 85% oil boiler closes about 12% of the gap, not the 55% difference in fuel cost per BTU. If you seek the tax credit, ENERGY STAR-certified gas furnaces qualify with an AFUE of 97% or higher, subject to a combined annual cap of $1,200.

Installation, Tanks, and Maintenance Reality

Upfront cost depends on what your basement already has, so we quote rather than publish a range. The main factors are whether existing venting can be reused, whether a condensing unit needs sidewall venting and a condensate drain, and the tank.

Oil means a tank you own, typically 275 gallons indoors. Propane means a tank you own or lease, and lease terms often tie you to that supplier for refills. Ask who owns the tank before signing.

Oil needs an annual tune-up that earns its cost: nozzle, filter, strainer, and a combustion efficiency test. Propane needs service less often but requires more specialized care. Condensing units add condensate and heat exchanger checks. Skipping service costs more than it saves on either fuel.

Emissions, Measured the Right Way

Propane looks dramatically cleaner per gallon and only modestly cleaner per unit of heat. EIA emissions coefficients assign 12.68 pounds of CO2 per gallon of propane, compared with 22.45 per gallon of heating oil. Per million BTU, the figures are 138.63 and 163.45 pounds, a gap of about 15% rather than the 44% the per-gallon numbers suggest.

That is where Bioheat fuel changes the calculation. Bioheat is ultra-low-sulfur heating oil blended with biodiesel and labeled by blend percentage; for example, B20 is 20% biodiesel. The renewable portion lowers lifecycle carbon in proportion to the blend, and it drops into existing oil equipment.

The Massachusetts Rule That Applies Only to Oil Heat

This is the obligation propane homeowners never face. Under Chapter 453 of the Acts of 2008, Massachusetts homes of one to four units heated with oil must have either an oil safety valve or a supply line enclosed in a protective sleeve. An oil safety valve stops fuel flow if the line cracks or separates.

The work requires a licensed oil burner technician. MassDEP puts the typical cost at $150 to $350, including parts, labor, and permits, compared with cleanup costs that reach $15,000 for a simple indoor leak. Systems installed on or after January 1, 1990, are usually already compliant. The law also requires insurers to offer oil leak coverage to compliant homeowners. If you are unsure where your oil tank is, ask at your next tune-up.

Pros, Cons, and How to Choose

Where Oil Wins

Lower cost per unit of heat, higher output for large or poorly insulated homes, long life on cast iron boilers, and a Bioheat path to lower emissions.

Where Propane Wins

Higher available efficiency, no supply line rule, flexible venting without a chimney, and one fuel that also runs a range, dryer, water heater, and generator.

Matching It to Your Home

If you are already on oil with life left in the boiler, the arithmetic suggests staying and considering Bioheat. If you are building, have no usable chimney, or want cooking and hot water on one fuel, propane earns its premium. Large older Worcester County homes usually come out ahead on oil. Switching purely to save money rarely pays off since you are buying equipment to buy costlier heat.

A Decade of Delivering Oil and Propane in Central Massachusetts

Marc Creegan became an oil and propane customer when he bought a home in July 2015, putting him in a position most homeowners debating this never reach: running both fuels with one supplier for a decade. What settled it was the unglamorous part. Account setup, equipment inspection, deliveries, and online billing went smoothly.

In his words:

“I became a CK Smith Superior oil and propane customer when I purchased a new home in July 2015. All of my dealings with them so far have been very pleasant, from the initial visit to set up my account to equipment inspections, oil deliveries, and online bill pay. Their online system is very easy to navigate, and being on automatic delivery ensures I always have oil.” Read Marc’s full Google review.

Nine years later, Marc updated the review to say he had stayed and trusted us for an emergency service call. That is what fuel choice comes down to in February: not the spec sheet but whether the company meets your needs.

Get the Real Numbers for Your Home, Not the Averages

We have delivered fuel and serviced heating equipment in Central Massachusetts since 1893 and have watched this comparison swing both ways through many price cycles. We deliver heating oil, Bioheat, and propane, and install and service equipment for both, so we have no reason to steer you toward the fuel we happen to sell.

Before deciding, ask for two things: the AFUE and age of your current equipment, and a combustion efficiency test. We will run those numbers, compare heating system options on both fuels against your usage history, and guide you to the best option.

Call (508) 753-1475 or reach out online for a personalized recommendation.

FAQs

Is propane cheaper than heating oil in Massachusetts?

Not on a delivered-heat basis in most conditions. Propane and heating oil have sold at similar per-gallon prices in Massachusetts recently. Still, a gallon of propane contains about 91,500 BTU, compared with roughly 138,500 BTU for heating oil, so a propane system burns far more gallons for the same amount of warmth. The Massachusetts Department of Energy Resources projected that the average propane-heated household would spend about $1,412 on winter heat for the 2025/26 season, compared with about $1,103 for the average oil-heated household. Compare quotes on cost per million BTU rather than per gallon.

Which system is more efficient, an oil boiler or a propane boiler in Massachusetts?

Propane equipment reaches higher AFUE ratings, commonly 90% or higher, because propane can run through condensing heat exchangers, while oil equipment generally tops out in the mid-80s. Higher efficiency does not automatically mean lower bills, though, since it must offset propane’s higher cost per BTU. A high-efficiency propane boiler, paired with expensive fuel, can still cost more to run than a well-maintained oil boiler. Have a technician test what your current system delivers before assuming a replacement will pay for itself.

Do heating oil systems require more maintenance than propane?

Oil systems need an annual tune-up covering the nozzle, oil filter, strainer, and a combustion efficiency test, and that visit matters more for oil than for propane. Propane equipment needs service less often, though condensing units add condensate drain and heat exchanger inspections that require specific training. Oil also brings tank and supply line inspection into the picture, which propane does not. Both fuels perform worse and fail sooner without annual professional service, so budget for it either way.

Is propane better for the environment than heating oil?

Propane produces less carbon dioxide, though the advantage is smaller than per-gallon figures suggest. EIA coefficients put propane at 12.68 pounds of CO2 per gallon, compared with 22.45 for heating oil, but measured per million BTU of heat delivered, the figures are 138.63 and 163.45 pounds, a difference of roughly 15%. Bioheat narrows that gap further by blending renewable biodiesel into heating oil, and it works in existing oil equipment without a conversion. If lowering emissions is the priority, consider a Bioheat blend or a heat pump paired with your existing system before switching fuels.

Is it worth switching from oil to propane in Massachusetts?

Rarely, for cost reasons alone, because you would be paying for new equipment to buy more expensive heat. Switching makes sense when there is a second reason: no usable chimney, a failed boiler that needs replacing anyway, a desire to run cooking, hot water, a dryer, and a generator on one fuel, or an addition that changes your heating load. Factor in the propane tank arrangement, since a leased tank can commit you to one supplier. Ask for a side-by-side estimate showing installed cost and projected annual fuel cost for both fuels before committing.

Key Takeaways

• Standard EIA conversion factors put a gallon of No. 2 heating oil at about 138,500 BTU and a gallon of propane at about 91,500 BTU, so one gallon of oil carries roughly the heat of 1.5 gallons of propane.
• For the 2025/26 season, Massachusetts DOER projected heating oil at an average of $3.10 per gallon and propane at $3.17 per gallon, which works out to about $22.38 and $34.64 per million BTU of fuel.
• DOER projected that the average Massachusetts oil-heated household would spend about $1,103 on winter heat, compared with about $1,412 for the average propane-heated household.
• Heating oil warms about 20% of Massachusetts homes and propane about 4%, making oil the far more commonly delivered fuel in the state.
• Propane equipment commonly reaches 90% AFUE or higher through condensing heat exchangers, while oil equipment generally tops out in the mid-80s.
• EIA emissions coefficients put propane at 12.68 pounds of CO2 per gallon and heating oil at 22.45, but per million BTU the figures narrow to 138.63 and 163.45 pounds.
• Under Chapter 453 of the Acts of 2008, Massachusetts homes of one to four units heated with oil must have an oil safety valve or a sleeved supply line installed by a licensed oil burner technician, at a typical cost of $150 to $350.
• Bioheat fuel is ultra-low-sulfur heating oil blended with renewable biodiesel and labeled by blend percentage, and it works in existing oil equipment without a system conversion.

Citations and References

• U.S. Energy Information Administration, British Thermal Units and energy conversion factors. https://www.eia.gov/energyexplained/units-and-calculators/british-thermal-units.php
• U.S. Energy Information Administration, Carbon Dioxide Emissions Coefficients by Fuel, released September 2024. https://www.eia.gov/environment/emissions/co2_vol_mass.php
• Massachusetts Department of Energy Resources, Massachusetts Home Heating Fuels Prices and winter heating cost projections. https://www.mass.gov/info-details/massachusetts-home-heating-fuels-prices
• Massachusetts Department of Environmental Protection, Homeowner Oil Heating System Upgrade and Insurance Law, Chapter 453 of the Acts of 2008. https://www.mass.gov/doc/homeowner-oil-heating-system-upgrade-and-insurance-law-0/download
• ENERGY STAR, Federal Tax Credits for Furnaces. https://www.energystar.gov/about/federal-tax-credits/furnaces-natural-gas-oil