Kerosene and fuel oil are both refined from the same barrel of crude oil but chemically they are different because they come from different steps in the refining process. These differences give both products an advantage depending on the application. Kerosene is recommended in outside tanks that are exposed to cold temperatures because of its better cold-flow properties. Heating oil is the better choice when the tank is in a basement or heated space where the temperature isn't an issue because it has a btu advantage over kerosene.