Two states have legislated rising biodiesel content in heating oil and more are moving. Nobody sells the correction that goes with it. A gallon of B20 is priced like a gallon of oil and delivers slightly less heat than a gallon of oil, and the difference is arithmetic rather than opinion.
The energy content table
| Blend | Btu per gallon | Energy against No. 2 | Cost per MMBtu at $5.54 | Effective premium per gallon |
|---|---|---|---|---|
| Straight No. 2 | 138,490 | reference | $39.97 | reference |
| B5 | 137,964 | down 0.38% | $40.12 | $0.02 |
| B10 | 137,437 | down 0.76% | $40.27 | $0.04 |
| B20 | 136,384 | down 1.52% | $40.58 | $0.09 |
| B50 | 133,225 | down 3.8% | $41.55 | $0.22 |
EIA State Heating Oil and Propane Program / W_EPD2F_PRS_NUS_DPG / published 30 March 2026 / checked 23 September 2026 / lag 177 daysthree to six months oldtier A
Last in-season print. The survey pauses after March and resumes in October, so this figure ages all summer.
What the correction is worth on a real fill
On a 261 gallon fill of B20 at $5.54, the energy shortfall against the same money spent on straight No. 2 is $22.32. Over a 900 gallon season it is $76.95. Neither figure is enormous, and neither is zero, and nobody tells you about either.
Which states require a blend
New York requires bioheat statewide, with the requirement stepping up over time. Connecticut has legislated a rising blend schedule with an eventual level far above where the market started. Other Northeast states have proposals at various stages. The right way to check is the state energy or environmental agency page, because the schedules amend.
The practical question for a household is not whether the mandate is good policy. It is what blend is in the truck this week, because that changes the arithmetic above, and the delivery ticket is where that answer lives.
What a blend does to the equipment
- Low blends up to about B20 run in standard equipment without modification in most cases. Check your burner manufacturer's stated limit rather than a general claim.
- Biodiesel is a solvent. On a first delivery into an old tank it will lift accumulated sludge, and the filter is the thing that catches it. Budget for one extra filter change after the switch.
- Cold flow behavior differs. In very cold storage, high blends can gel earlier than straight No. 2. This matters for an outside tank far more than a basement one.
- Higher blends can require seal and hose compatibility checks on older systems.
Why nobody publishes this
Because the answer is slightly awkward for everyone. The mandate is defended on carbon grounds, which is a legitimate argument that does not require pretending the energy content is identical. Publishing the correction is not an argument against blends. It is just the number.
Primary sources for this page
- Alternative Fuels Data Center, biodiesel blendsEnergy content and blend handling guidance for B5 through B100.
- EIA State Heating Oil and Propane ProgramWeekly residential delivered price of No. 2 heating oil, national and by state. Collected October to March. The survey pauses after the last March print and resumes in October, which is why every federal page shows March data all summer.
- Connecticut DEEP heating oil pricesState weekly dealer survey, published through the heating season.
- New York State petroleum business registrationsRegistration rather than a consumer-facing dealer licence. Read the distinction on the dealers pages.