Heating oil is a low-viscosity refined fuel product derived from crude oil. Its principle use is in furnaces and boilers that heat residences and businesses. As an alternative fuel source, heating oil is popular in areas where natural gas and propane are either too costly or unobtainable, such as the northeastern United States and parts of the United Kingdom. Heating oil is second only to gasoline in terms of products derived from crude oil. Its crucial role as a source of heat in the winter months makes heating oil an important commodity in the global economy. Heating oil production takes place in oil refineries. These industrial facilities separate crude oil, which consists of different hydrocarbons, into smaller component hydrocarbons known as fractions. Refineries heat the crude oil at temperatures of several hundred degrees and put the boiling liquid into distillation columns called stills. The boiling process produces heating oil as well as other fractions such as kerosene, gasoline and butane. Each of these products is recovered at different temperature points in the boiling process. Distillates, including heating oil and diesel, are generally recovered at temperatures between 450 to 650 degrees Fahrenheit.