Oil heater
Oil heaters consist of metal columns that are hollow inside, where heat transfer oil flows freely around the heater. A heating element at the base of the heater heats the oil, which flow the heater by convection and then to the area around the heater by air convection and thermal radiation. The columns of oil heaters are constructed as thin fins so that the surface area of the metal columns is large compared to the amount of oil and element which provides the warmth. A large surface area allows more air to be in contact with the heater at any point in time, allowing for the heat to be transferred more effectively. This results in a surface temperature that is safe enough to touch. The heating level is controlled by a thermostat.