I’ve tried both oil-filled radiators and electric heaters — this is how they really differ, and why one will be more suitable for you than the other

If you're looking for a secondary heating option to complement your central heating on the chilliest of days, then you might be thinking about investing in an electric heater of some type.

The best electric heaters come in a variety of guises — including fan, convection and infrared — plus there's the best oil-filled radiators to consider too.

You could be forgiven for thinking that oil-filled radiators and electric heaters are the same thing. After all, they are both portable electric appliances that are used to provide heat. That's definitely what I used to think. But after using both oil-filled radiators and electric heaters myself, I finally understand that they are actually more different than they might seem. Here's how.

What's the difference between an oil-filled radiator and an electric heater?

While both electric heaters and oil-filled radiators are powered by electricity and have similar price points, they have key differences that set them apart from each other.

Heat distribution

'Oil-filled radiators and electric radiators are similar in the way these both use electricity as their power source, but the key difference lies in how they distribute heat,' explains Stephen Hankinson, heating expert at Electric Radiators Direct.

'Oil-filled radiators heat up thermal oil inside the unit, transferring warmth into the metal, which emits heat into the room through radiation. Heat is then circulated around the room as any air that passes against the radiator is warmed up.'

On the other hand, electric heaters work differently. Some electric heaters have a ceramic core, which is heated with electricity, and then a fan helps distribute the warmth, while others might use heated metal coils to generate the warmth. In the case of infrared heaters, these are designed to emit electromagnetic radiation that, rather than heating the air, heats objects, surfaces, and people directly instead.

Speed of heat and heat retention

One of the most obvious difference I noticed between the two is that electric heaters tend to produce heat almost instantly, whereas oil-filled radiators take longer to reach the chosen temperature.

While it takes longer for the thermal oil in a oil-filled radiator to heat up then it does for an electric fan or ceramic heater to warm up, but once that oil is warm, it doesn't cool down quickly. Instead it retains the heat and will carry on emitting warmth even after it's turned off. That means they are best used for more steady heating over longer periods of time.

Electric heaters, on the other hand, generate pretty much instant heat but cool down very quickly after being switched off. That means they are best suited to areas where you need a quick burst of heat, but maybe don't need the space to be warmed for long periods.

Which is cheaper to run - an electric heater or an oil-filled radiator?

Whether you are using an oil-filled radiator or an electric heater, running costs will depend on the wattage of the appliance, the mode you use it in and how long you use it for.

For example, the running costs for the oil-filled radiators that made it into our round up of the best you can buy, range from 500-2500W. Based on price per kilowatt hours of electricity under the current January 2026 energy price cap that means they can cost anywhere between 14p and 69p an hour to run.

Compare that to the electric heaters that made it into our best buy guide, that have wattages between 700W and 2500W, the running costs are very similar.

However, with better heat retention, oil-filled radiators are generally considered the more efficient of the two. One thing you should consider before buying an oil-filled radiator is the fact they continue to emit heat after they are turned off and that they can still be effective despite being used for shorter periods of time. This gives them an edge over electric heaters from a cost to run point of view.

Which is noisier - an oil-filled radiator or electric heater?

I can attest that oil-filled radiators are silent in operation, while electric heaters with a fan will create a noticeable sound when in use, and it will usually be louder in the more powerful modes.

However, not all electric heaters make a noise when in use. I recently reviewed the Mill WiFi Max 1500W portable heater, which was practically silent in operation.

This may not bother some people, but if you are sensitive to sound you may find the noise of fan heaters distracting.

Which is better for large spaces - and oil-filled radiator or an electric heater?

Provided you choose an appropriately-powered appliance, you could use an electric heater or an oil-filled radiator to heat a large room.

But larger rooms or open plan zones can be notoriously difficult to heat, and even if you are complementing your central heating with an electric heater, you'll need a more powerful model than will come with higher running costs. Plus, you may find you want it on for longer to continue to feel the benefits until your central heating kicks in again.

However, the heat retention benefits of an oil-filled radiator could make it a more suitable and cost-effective option.

On the other hand, if you are looking to heat a smaller room, then it's a good idea to choose something with a smaller wattage. A good rule of thumb is to allocate 100W per m2.

You might also be concerned about the actual dimensions of your chosen emitter too. While you can get oil-filled radiators will fewer fins, the best space saving options can usually be found in the electric heater category.

Which should you choose - an oil-filled radiator or electric heater?

In my experience, there's no one-size-fits-all answer to whether you should pick an oil-filled radiator or an electric heater. Instead it depends on your specific home, the room you want to heat and how you want to heat it.

If you want something with silent operation that will efficiently heat a large room for long periods of time, then an oil-filled radiator is likely to be the better option for you. However, if you don't mind the noise and want an emitter that provides a short burst of heat, then an electric heater might be more your bag.

A spokesperson from De'Longhi, who manufacture both oil-filled radiators and electric heaters, shared this quick glance table with me to help you choose the best option for your home.

If you do end up deciding that an oil-filled radiator is the right fit for you and your home, make sure you know how to use it most efficiently for maximum benefits with the lowest energy consumption.