Oil heater

The columns of oil heaters are typically constructed as thin fins, such that the surface area of the metal columns is large relative to the amount of oil and element that provides the warmth.

The relatively large specific heat capacity of the oil and metal parts means this type of heater takes a few minutes to heat up and cool down, providing short-term thermal storage.

Many heaters (the majority of available models) are equipped with a thermostat to prevent this inefficient heating, which in turn reduces running costs.

[1] A 500-watt heater will take at least twice as long to reach the same thermostat setting as a 1000-watt unit; however, the total electricity consumption will be the same for both.

Additionally, the rate of heat flow from a heater to the air directly in contact with it is higher when there is a greater temperature difference between the two.

In both regards, they are generally more dangerous than heat pumps, hydronics, and air conditioning, but less dangerous than electric fan heaters or bar radiators, due to the surface temperature of any given type of heater.

Oil heaters have been known to explode when their thermal fuses fail to trigger a shutdown,[4] which can cause fire, thick black smoke, unpleasant odors, oil on walls and other surfaces, and disfiguring scalding.