Heating oil

Heating oil, or oil heat, is a low viscosity, liquid petroleum product used as a fuel oil for furnaces or boilers in buildings. Home heating oil is often abbreviated as HHO.

Heating oil consists of a mixture of petroleum-derived hydrocarbons in the 14- to 20-carbon atom range that condense between 250 and 350 °C (482 and 662 °F) during oil refining. Heating oil condenses at a lower temperature than petroleum jelly, bitumen, candle wax, and lubricating oil, but at a higher temperature than kerosene, which condenses between 160–250 °C (320–482 °F). The heavy (C20+) hydrocarbons condense between 340–400 °C (644–752 °F).

Heating oil produces 138,500 British thermal units per US gallon (38.6 MJ/l) and weighs 8.2 pounds per US gallon (0.95 kg/l).Number 2 fuel oil has a flash point of 52 °C (126 °F).

Most heating oil products are chemically very similar to diesel fuel used as motor fuel. (Often the same distillation batch could be used for either purpose.) This means that the two can often be successfully interchanged at the point of use. However, the taxation of the two differs in many places, with heating oil being taxed less than motor fuel. This creates an incentive to buy heating oil at a lower price and then use it as motor fuel, avoiding the fuel tax. To make enforcement possible, some visual difference or odor difference must be introduced to the oil. Therefore, red dyes are usually added, resulting in the "red diesel" name in countries like the United Kingdom. In the U.S. the fuel oil dyed red is not taxed for highway use; the dye makes it easy to identify its use in on-road vehicles (whereas diesel fuel sold for motor fuel use is usually green). Since 2002, Solvent Yellow 124 has been added as a "Euromarker" in the European Union.