Efficiency & Cost to Run Oil Filled Radiator Heaters

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Brad Smith
Written By Brad Smith

Oil filled radiator heaters offer a reliable way to supplement your central heating system and lower your utility bills.

These heaters offer both power and flexibility necessary to warm rooms up to 150 square feet and compensate for all under heated rooms in your house.

In these kind of situations, the easiest way to ensure a even and stable temperature is with an efficient space heater.

Unlike convection heaters that transfer heat directly to the surrounding air, or radiant heaters that heat objects and people, oil filled heaters first heat oil inside them, which then gradually lets oil heat your house in a controlled way, creating stable and even temperature.

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The unique thermal properties, combined with their easy transportability, makes oil filled room heaters one of the most energy efficient and reliable way to heat your rooms in your home, workspace, or office. 

How These Oil Filled Radiator Heaters Work?

  • Oil filled heaters come with a built in stacked radiator fins, or maybe a larger flat panel. 
  • The panel and finds are filled with special diathermic oil and are further connected to a separate electric sensor in the control panel.
  • Once the heater is plugged in, the electricity activates the resistor, which starts converting it quickly into heat.
  • This heat is absorbed by the oil present in the body of the space heater.
  • Once the oil warms up, it starts circulating through channels that are built into flat panel and radiator fins transferring its heat to the metal exterior of the heater through thermal conduction. 
  • Once the metal warms up, it will heat air through thermal convection. Air close to the heater absorbs most of its heat and rises, drawing more of the cool air that’s again heater in turn. 
  • This will create convection current that distributes this heat evenly throughout the room.
  • You will gradually notice that cost to run oil filled heaters is much less than other available options.

Cost to Run Oil Filled Heaters

Oil filled heaters are highly mobile and due efficiency of oil filled heaters they draw small amount of power, as compared to a furnace (500-1600 watt on an average), so you can easily heat strategically to quickly optimize your environment.

These heaters carry handles that allow them to be easily picked and moved without any risk of injury or burns. Many models even have castor wheels to make it easy to transport around the house or office. 

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Due to their excellent energy saving properties, these heaters are more economical in terms of heating and maintenance. They use very little energy to charge up its special oil preserves energy used. This results in saving good money in the long run. The best thing is that these heaters are very affordable. 

They run on full power when initially switched hence consume very less power. So if your heater is rated at 2KW and runs for 4 hours, it will consume just 8 unites. 

Efficiency Of Oil Filled Heaters

Oil filled heaters are over 99% more energy efficient than other heating options. All the electricity consumed by them converts to heat.

Just small amount (less than one percent) of it is diverted and used for operating the control panel and some extra heater features depending upon the model you are using. Some heaters may use thermostat, and energy settings modify the amount of electricity heater uses. 


However, the biggest reason for efficiency of oil filled heaters is the unique thermal properties of the oil. Diathermic oil comes with better heat capacity that is the amount of energy a substance can actually absorb before its temperature increases one degree. 

High heat capacity helps in maintaining better absorption of large amounts of heat. It’s a kind of heat reservoir that allows unit to continue radiating heat even while resistor has been deactivated. This means once the room has reached required temperature, the oil filled heater needs less power to maintain it. 

Space heater monitors temperature using built-in thermostat that triggers resistors whenever temperature drops below a present level.

Since the resistor can consume most of the electricity used by a space heater, the less often it is activated, the more efficient your space heater will be. Oil field space heaters that can radiate heat without using any resistor are more energy efficient of them all. 

Reasons for Efficiency of Oil Filled Heaters

The biggest benefit of using oil filled radiator heaters is that they have better mobility and can be moved around the house with ease, allowing you to concentrate their heat in a better way to the place where it’s needed the most.

The biggest issue with central heating is its heat output depends on the average temperature of the air which is returned to it via central heating ducts.Because the air is an aggregate, drawn from air present all over your house, air from the warmest areas of your house will mask colder air form the coldest areas, so it becomes cumbersome to maintain an even temperature throughout the day.

There are many factors that may affect temperature in your house-leaky windows, sun exposure, degree of insulation-so it’s not easy to program a furnace thermostat to accurately compensate for them all.

Oil filled heaters offer the flexibility that allows you to easily overcome this difficulty.

Comparison to Water Filled Space Heaters

Water filled heaters operate like oil filled heaters. They are constructed with series of specially built stacked metal radiator fins filled with some water. Water heats through hating coil or boiler which results in its expansion and circulation within the structure, transferring sufficient heat to the metal, which then transfers it out of the room through natural convection.

Hot water can be pumped in and speedily circulated through the heater by connecting it directly to boiler or hot water heater. Water filled heaters are older types of heaters and benefits of oil filled heaters are making them less desirable heating solution. Water filled heaters are not portable and are fixed at one place. They need to be fixed at just one place once they are installed, so they don’t possess the same kind of heating flexibility as oil filled heater. There are not portable mainly due to the low boiling point.

Because they are normally heated to 165-185F, these heaters need additional support to contain all the vapor pressure of water as it reaches boiling point.

The diathermic oil radiator filled heater possess a boiling point at least three times higher than water, so it maintains liquid state during operation, which means the heater will never function as a high pressure vessel, ensuring their portability and light. 

How You Know You Need an Oil Filled Heater

If you’re not sure you need a oil filled space heater, just check to see how well your furnace heats up your house. Heating each room to a set temperature is not a easy.

If your temperature is set to a desired temperature, and then you find some of your rooms are still chilly, an oil filled heater is the best remedy. They’re just what you need in the rooms with poor insulation, big widows, or drafts.

If you’re interested in saving some money, just turn down the thermostat by few degrees to a point where it’s just comfortable for you, and start using an oil filled heater to further warm up only the rooms you are using at the moment.

If cost of heating few rooms is less than half the cost to heat the entire house, you are losing big money by not supplementing central heating with a worthy best oil-filled radiator heater

Further Reading

  • For those looking to extend warmth into every corner of their home, including smaller, more intimate spaces like bathrooms, our comprehensive guide on the Best Portable Bathroom Heaters offers expert advice and top recommendations to ensure you find the perfect heating solution tailored to your needs.
smith brad omni

Written by Brad Smith

CEO & Lead Interior Designer

Brad Smith is an experienced interior designer and the founder of OmniHomeIdeas.com. With a Master's degree in Interior Design from Pratt Institute and a passion for creating safe and healthy living spaces, Brad shares his expert insights and innovative design ideas with our readers. His work is driven by the belief that home is where every story begins.