Oil heater

An oil heater, also known as an oil-filled heater, oil-filled radiator, or column heater, is a form of heater used in home heating. Although they are filled with oil, it is electrically heated and does not involve burning any oil. 

Function
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.

Efficiency
Oil heaters cost more to run and provide far less heating than gas heaters, they are still used in bedrooms and other small-to-medium-sized enclosed areas. This is because gas heaters, especially without a flue, are not suitable for bedroom use. Gas heaters cannot be used in confined spaces due to the reduced oxygen, and the emissions produced. This leaves electrically powered heaters, such as oil heaters, fan heaters, and heat pumps, as the only alternatives. 

References

Category:HVAC
Category:Heat
Category:Home appliances