Heating oil is chemically almost identical to diesel fuel, yet regulators have historically allowed it a higher sulfur threshold and a separate tax treatment, distinctions that shape how terminals store, dye, and dispense the two products. Understanding what is heating oil means understanding a distillate fuel that splits into two distinct grades depending on the market it serves.
What Is Heating Oil?
Heating oil is a petroleum distillate fuel used in boilers and furnaces to heat buildings and water, most commonly in properties off the mains gas grid. It is produced from the same fractional distillation process as diesel, condensing from crude oil vapor in the 14- to 20-carbon-atom range, between roughly 250°C and 350°C, placing it between kerosene and the heavier diesel and lubricating oil fractions on the distillation tower.
Two grades dominate the market. Kerosene heating oil, the lighter and more refined grade, is the standard for UK and Irish domestic central heating, sometimes called 28-second oil based on its viscosity rating. Gas oil, the heavier and less refined grade, serves commercial heating, agriculture, and older boiler systems, and is functionally identical to red diesel in the UK market. In the US, the equivalent product is designated No. 2 heating oil under ASTM D396.
The historical legal distinction between heating oil and diesel came down to sulfur content: US road diesel has long been capped at 15 ppm, while heating oil was permitted up to 500 ppm. Most US heating oil sold today is ultra-low-sulfur heating oil (ULSHO), meeting the same 15 ppm standard as diesel, which has narrowed the technical gap between the two fuels even as the regulatory and tax distinctions remain in place.
Where Is Heating Oil Produced or Stored?
Heating oil follows the same bulk logistics chain as other refined distillates: pipeline and tanker movement from refinery to regional storage terminals, followed by barge or rail distribution to secondary terminals, and final delivery to end-users by road tanker. Refining and distillate logistics mirror the chain OGSN covers for diesel, with which heating oil shares both feedstock and a meaningful share of refinery output.
At the consumption end, storage looks markedly different from diesel’s commercial and industrial tank network. Domestic heating oil is typically held in bunded plastic or steel tanks of 1,000 to 2,500 litres, sited externally on a concrete base away from property boundaries and fire hazards. Commercial and municipal users rely on larger above-ground or underground tanks, with UK installations governed by the Control of Pollution (Oil Storage) Regulations 2001 and Building Regulations Approved Document J, both requiring secondary containment bunds sized to at least 110% of tank capacity.
Bulk terminal storage for heating oil sits within the same tank infrastructure used for diesel and other middle distillates, an overlap OGSN’s crude oil storage costs coverage extends to the broader distillate storage economics question of shared tankage versus dedicated capacity.
Heating Oil Storage Regulations and Compliance
UK regulations treat heating oil storage as a pollution-control issue first and a fire-safety issue second. Tanks must demonstrate sufficient strength and structural integrity to avoid bursting or leaking in ordinary use, and any fill pipe routed outside the bunded area requires a drip tray. Siting rules are specific: new tanks must sit at least 1,800mm from doors, windows, and non-fire-rated structures such as garden fences, and at least 760mm from smaller non-fire-rated structures.
Fuel dyeing is the primary enforcement mechanism for tax compliance across heating oil markets. The EU has used Solvent Yellow 124 as a Euromarker since 2002, while the UK’s red diesel dye distinguishes untaxed agricultural and heating fuel from taxed road diesel at the pump and in storage. Terminal operators handling both grades must maintain physically separate tank, line, and dispensing infrastructure to avoid cross-contamination and the substantial fines that follow a compliance failure.
Heating Oil Price and Market Context
Heating oil pricing in the US tracks the New York Harbor No. 2 heating oil futures contract, traded in units of 1,000 barrels, with seasonal demand concentrated in the northeastern states of New York, Pennsylvania, and New England, which together account for roughly 85% of US residential heating oil consumption. The US Energy Information Administration publishes weekly heating oil price data through each heating season, alongside historical series covering all major US markets.
For current benchmark figures across US, UK, and global markets, see OGSN’s heating oil price tracker, updated monthly with full storage economics context.
What is heating oil and how is it different from diesel?
Heating oil is a petroleum distillate fuel used in boilers and furnaces, refined through the same fractional distillation process as diesel and sharing a near-identical chemical profile. The historical distinction is sulfur content and tax treatment rather than chemistry, though most US heating oil now meets the same 15 ppm sulfur standard as road diesel.
What is the difference between kerosene and gas oil heating fuel?
Kerosene is the lighter, more refined grade used in most UK and Irish domestic central heating systems. Gas oil is heavier, less refined, and used mainly in commercial heating, agricultural settings, and older boilers, where it is functionally equivalent to red diesel.
Where is heating oil stored?
Domestic heating oil is stored on-site in bunded above-ground tanks of 1,000 to 2,500 litres, typically sited externally on a concrete base. Commercial and bulk terminal storage uses larger above-ground or underground tanks within the same distillate storage infrastructure used for diesel.
Why is heating oil dyed red in the UK?
Red dye marks untaxed heating and agricultural fuel to distinguish it from taxed road diesel, allowing enforcement bodies to detect tax evasion. Terminal operators handling both grades must keep tanks, lines, and dispensing equipment physically separate to prevent cross-contamination.
What regulations govern heating oil tank storage in the UK?
UK heating oil tanks fall under the Control of Pollution (Oil Storage) Regulations 2001 and Building Regulations Approved Document J, both requiring secondary containment bunds at 110% of tank capacity. Siting rules also set minimum distances from doors, windows, and boundary structures.
Where can I find the current heating oil price?
OGSN tracks the live heating oil price across US, UK, and global benchmarks, updated monthly with storage economics context.