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Oil Heaters: How Efficient They Are Compared to Other Space Heaters?

Oil heaters are one of the most popular heating solutions available on the market. They are also known as oil filled radiators or column heaters. Many people think oil heaters use oil as their fuel because of their name. But in reality, oil heaters work on electricity and oil is used only as a reservoir of heat. The reason behind this is the excellent diathermic properties of the oil. Although oil needs a bit longer time to warm up, it can retain heat for a long period of time as diathermic oil has a low vapor pressure, high boiling point and low pour point.

The use of diathermic oil has added some extra advantages to oil heaters and it also has a significant impact on its energy efficiency.

How Do Oil Space Heaters Work?

Oil heaters or oil filled radiators use electricity to generate heat. They consist of electric resistors, “fins” and metal exterior. Electric resistors are responsible for converting the electric energy to heat energy. The heat energy produced is transferred to the fins. These fins contain diathermic oil. When the heater is plugged in, the electric resistor gets on and starts to heat up the oil contained fins. When these oil contained fins are heated to a certain level of temperatures, the heat is channeled to the metal exterior of oil heater via some built-in tunnels through solid conduction process. Then the heat is transferred to the targeted area by heating up the surrounding air through the convection process. In the convection process, the hot gas or liquid molecules go up and make space for cooler gas or liquid molecules. Thus creating a circulation by which the heat is transferred.

The whole heating process of oil heaters requires a lot of time in comparison to such other space heaters as infrared or fan heaters. The main reason behind this is the high boiling point of the diathermic oil. But on the other hand, once heated properly, oil heaters can retain heat for a longer period of time even after they are switched off.

Advantages of Oil Heaters

Energy Efficient Heater:

Oil filled heaters efficiency is significantly higher than other space heaters. The inclusion of diathermic oil has enhanced their heat retaining capacity in many ways. Oil filled radiators can provide heat for a period of time even after they are switched off. Moreover, there is a temperature monitoring system which automatically triggers the electric resistors on and off. That means when your room temperature is warm to a certain level the electric consumption of the heater will be halted. If the room temperature falls, the electric resistor, responsible for converting heat from electricity, will turn on again without needing any manual effort.

Radiant Heating:

Unlike other space heaters, oil filled heaters don’t use fans to transfer the heat into the surrounding air. They use the radiant heating system in which the highly energized molecules of warm objects (oil filled fins) transfer their heat to less energized molecules of cooler objects (room’s air). Radiant heating has many advantages. Unlike the fan heating system, it doesn’t promote the movement of germs and dust through air circulation.


Oil space heaters are noise free since they don’t use fans to transfer heat. Normally in other heaters, the movement of fan blades makes a constant noise which is annoying to most of us. Oil heaters don’t generate any sort of noise. If you are looking for a peaceful heater, oil filled heaters might be the solution.


Among all the space heaters oil heater is the safest heating option for you. They come in one single piece and the diathermic oil inside it is kept sealed in metal chambers, which eliminates the risk of any spillage. Furthermore, oil heaters require very little maintenance.

Strategic Heating:

Oil heaters are available with many variations in their size. You can choose the size which meets your needs. Most of them are portable and you can heat any of your rooms with an oil heater. You can also heat your rooms strategically one by one with an oil heater.

Disadvantages of Oil Heaters

Slow Heating

Oil filled radiator heaters do require some time to warm up the room because oil has a high boiling point than water. Furthermore, the heat is transferred via a convection process which also needs time to transfer the heat to the target objects. Similarly, oil heaters take time to cool down after they are switched off. If you are looking for a quick heating solution, oil heaters will not be suitable for you.

Higher Price

Although oil heaters have less operating cost than other space heaters, they are more costly to purchase in comparison to the other space heaters. The use of diathermic oil as a heat reservoir is the main reason for this higher cost.

Ineffective in Uninsulated Large Rooms

Like most space heaters which work based on the convection principle, the oil heaters are also ineffective for larger rooms or uninsulated rooms. The reason behind is that in an uninsulated room the warm air moves away to the outside atmosphere and cool air gets in, which hampers the convection heating process. Infrared heaters are the best option for such places.

Oil Filled Heaters Efficiency

Oil heaters are a smart heating solution if you consider all the aspects of a space heater. There is no single space heater which is perfect in all regards.

In terms of operating cost, central gas heaters for home use are the most economical solution but they are not portable and flexible enough for a single space solution. The oil filled radiator heater is the second most economical solution which is also very flexible by design. They are economical than other space heaters because of their thermostat features.

If you are worried about the safety issue then buying an electric oil heater or ceramic heater would be the best decision for you because they come in one piece and don’t have any spillage or electrocution risk.

If you want the quickest and most effective heating solution for you then you should pick an infrared heater. But infrared heaters have higher installation costs than oil filled heaters.
Finally, oil heaters are an efficient solution providing all the desired features more or less in an adjustable manner. They are safe, economical, and effective for small or medium size household uses.

How to Choose the Best Oil Heater?

Now that you know the pros and cons of oil heaters and oil filled heaters efficiency in comparison to the gas heater and other types of space heaters, you can choose whether oil heating for home is suitable for you. If you decide to buy an oil heater, you should be careful about the following aspects.

Room Size

The size of the room in which you are intending to use the oil heater should be the first concern before making a buying decision. Choosing a smaller size oil heater than the required size would make your heating process ineffective and choosing a bigger one would also make it inefficient. So you must choose an oil heater which is perfect for your intended room size. Usually, a 1500 watt oil heater is perfect for a medium or large room.


It is imperative to check if your oil heater has any safety features. Many new models have various safety features, such as the auto shut off feature that enables automatic shut down when the room temperature reaches the desired temperatures. There is another safety option that can be seen in many oil heaters that monitors if there is any tipping over of oil from the oil chamber. This feature would instantly shut down the heater if it detects that.


Oil filled space heaters are generally heavy in weight. Although they come into smaller sizes, it might be hard to carry them around due to their weight. That’s why most oil heaters have attached wheels. You should check the portability feature of your chosen oil heater before your purchase.

Thermostat Feature

The thermostat feature is the auto temperature monitoring system. The system constantly compares the room temperature with the oil containing metal fin’s temperature. If the room temperature reaches a certain level, then the thermostat feature would automatically shut down the heating process. And it will start automatically when it needs to. If your oil heater has this smart feature, it would save you a lot of money.

Material in Use

Oil filled space heaters generally come in one piece and they don’t require maintenance other than surface cleaning. It is worth checking whether the material used on the surface of the oil heater is rust free or not. Oil heaters can provide heating service for a long time and rust-free material can enhance this duration even further.

Finally, using an oil heater could be a wise solution for your home heating problem considering that they have a perfect blend of a safe and energy efficient heater. These features together make an oil filled heaters most suitable for household uses that require very little maintenance.

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1 Comment

  • Warning: Undefined array key 180 in /www/wwwroot/ on line 402
    Jhon Martin says:

    Nice blog. It will surely help beginners update their knowledge. The efforts you have put in to create the posts are quite interesting. Looking forward to seeing you soon in a new post.

    However, you may feel that they are at a loss when confronted with a wide variety of oil filled heater available these days.

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