Which is cheaper to heat with — oil or propane?
No. IStart with energy density, because it's the fact that doesn't change. Per the EIA, a gallon of No. 2 heating oil holds ~138,500 BTU and a gallon of propane ~91,452 BTU — so you need about 1.5 gallons of propane to equal one gallon of oil. A raw price-per-gallon comparison is therefore misleading; propane looks cheaper per gallon but you burn more of it.
The honest comparison is cost per delivered MMBtu — the fuel's price divided by its usable energy (energy content × your equipment's AFUE efficiency). That method stays true as prices move, which is why it beats quoting a snapshot. Worked out with realistic early-2026 RI/MA prices:
- At normal prices, oil wins. Around $4/gal in a standard 85%-efficient oil boiler is roughly $35/MMBtu — cheaper than propane near $3.64/gal even in a 95% condensing unit (~$42/MMBtu). Oil's energy density carries it.
- During an oil-price spike, it can flip. When heating oil runs sharply above its normal range while propane stays comparatively steady, the per-MMBtu math can tip toward a high-efficiency (condensing) propane system — propane's price stability plus condensing efficiency can neutralize oil's energy-density edge. Which way it lands depends on the day's prices, so run the same per-MMBtu math on current figures.
The takeaway isn't "oil" or "propane" — it's run the numbers on today's prices with your equipment's efficiency. Check current RI/MA oil prices on the live Rhode Island or Massachusetts pages (RI is currently averaging $5.15/gal) and redo the per-MMBtu math; propane you'll price from your local dealer. (AFUE bands: oil equipment typically 80–90%, condensing propane 90–98%, per DOE/ENERGY STAR.)
See also: Rhode Island heating oil page, Massachusetts heating oil page
How do the two fuels differ to live with?
No. IIBeyond cost, the fuels behave differently day to day:
- Combustion & maintenance. Heating oil is a heavier hydrocarbon — it produces soot and carbon deposits, so oil systems want a real annual service (heat-exchanger cleaning, nozzle and filter swaps). Propane burns cleaner with far less residue, so service is lighter.
- Safety profile. Liquid heating oil isn't explosive — it must be atomized and heated to ignite, and a leak is visible. Propane is stored under pressure and flashes to a flammable vapor if it escapes, so it's odorized (the "rotten-egg" additive) as a leak warning. Different risk shapes, neither disqualifying.
- Environmental risk. This one favors propane: a propane leak vaporizes and disperses, while an oil spill can soak into basement concrete and soil and trigger expensive remediation. It's a real reason some homeowners near wells or wetlands prefer propane.
Which fuel do RI/MA homes actually use?
No. IIIDelivered fuels dominate outside the natural-gas corridors. Per U.S. Census ACS data, heating oil still warms just over a quarter of Rhode Island homes and about a fifth of Massachusetts homes, while propane serves only ~4–5%. So in southern New England oil is the incumbent and propane the specialized choice — which matters for dealer competition and service availability (there are simply more oil dealers competing for your business — the full-service vs COD guide covers how to use that).
One oil-specific wrinkle: Rhode Island now requires a rising biodiesel blend in heating oil — B20 (20%) as of 2025, heading to B50 by 2030 (under the 2013 Biodiesel Heating Oil Act, as amended in 2021). Biodiesel is a mild solvent, so a first high-blend delivery can loosen old-tank sludge and briefly clog a filter. Massachusetts has no statewide mandate (its Alternative Portfolio Standard gives credits for B10-and-higher blends).
See also: full-service vs COD guide
Should I lease or own a propane tank?
No. IVIf you go propane, this is the decision that bites later. Leasing is cheap up front (~$50–$250/yr, dealer handles inspections) but locks you to that dealer's pricing — you can't shop around. Owning ($400–$2,000) costs more up front but lets you buy from any dealer.
Rhode Island protects lessees here: under R.I. Gen. Laws § 5-83-5, when you end a propane contract the distributor must remove a leased aboveground tank within 20 days, refund your remaining propane within 30 days, and can't charge a removal fee if the tank's been in place over 3 years. (Massachusetts has a similar bill, H.2844, but it's proposed, not yet law.) It's a real reason RI switching is less painful than homeowners fear.
What about switching fuels — or going to a heat pump?
No. VTwo adjacent decisions worth flagging, each with its own full guide:
- Oil→propane conversion is a big capital project — new equipment, tank, gas lines, venting, and (if a buried oil tank leaked) remediation. It rarely pencils out while your oil system still works; it's mainly worth it when the equipment has failed anyway — a big enough decision to cost out carefully before committing.
- A heat pump is increasingly the third option. Both states now push electrification hard — Massachusetts' Mass Save has ended rebates for new fossil-fuel systems (oil, gas, and propane) and steers incentives to heat pumps. One verified detail favors propane in a hybrid setup: Mass Save's integrated controls switch a heat pump to its backup at 30°F for an oil backup but can run down to 5°F for a propane backup — so propane lets the efficient heat pump work in colder weather. Rebate terms shift year to year, so check the current Mass Save / Clean Heat RI offers before deciding.
Readers Ask — Related Questions
Can I store propane in my old oil tank?
No. Heating oil sits in a non-pressurized 275-gallon steel tank; propane must be stored under pressure in a rated steel cylinder. Switching fuels means a new tank, not a repurposed one.
Is it better to lease or own a propane tank?
Leasing is cheaper up front but ties you to one dealer's prices; owning costs more initially but lets you shop every fill. In Rhode Island, § 5-83-5 makes ending a lease easier (tank removed in 20 days, propane refunded in 30, no removal fee after 3 years).
If oil is usually cheaper, why would I pick propane?
Cleaner burning and lighter maintenance, lower spill/remediation risk, competitiveness during oil price spikes, and — if you're adding a heat pump — a colder hybrid switchover point under Mass Save's integrated controls in Massachusetts (5°F for a propane backup vs 30°F for oil). It's a convenience-and-resilience trade, not purely a price one.
Sources
- i.EIA — Energy content of fuels, Btu per gallon
- ii.EIA — Massachusetts Weekly Heating Oil Prices
- iii.DOE / ENERGY STAR — furnace & boiler AFUE efficiency
- iv.U.S. Census Bureau — ACS house heating fuel, table B25040
- v.RI DEM — Biodiesel Heating Oil Act
- vi.R.I. Gen. Laws § 5-83-5 — propane tank lease termination
- vii.Mass Save — heating & cooling incentives
Prices are scraped from public sources and may not reflect current rates. All listings are unverified.