Oil filled heaters uses electrical power to heat a sealed oil reservoir. The liquid releases warmth into the atmosphere gradually, slowly heating the entire room. It takes a little time to heat the oil and circulate warm air around the room. Oil heaters are by far the most economical electric heater. It takes little extra electricity to maintain the temperature after the initial heating. Oil heaters are in the mid-price range, and the lack of moving parts ensures that they are sturdy and durable.

The economy and gentle heat generated by oil heaters makes them a great option for providing permanent heat the whole day and night. Oil heaters are the safest option, and can be left to run overnight with less danger than any other electrical appliance.

Oil heaters have some disadvantages, and are not always the best solution. The main downside is that they do not deliver instant heat, and need to be turned on an hour or two in advance. Besides, oil heaters heat the entire room so everybody has to endure the same temperature. Finally, larger oil heaters are heavy and cumbersome, so are best used as a static heat source.

Apart from oil-filled heaters, there is another kind of heater called fan convection heater. Fan convector heaters use an inbuilt fan to force air over an element, offering quick heat and good air circulation. Fan convection heaters are available in a range of sizes and capacities, from the small desktop heaters to larger freestanding types. Many natural convection heaters give the option of using a fan, and this hybrid type provides the best of both worlds.

Like oil-filled heaters, box fan convection heaters have some major drawbacks, and should be used sparingly. The inbuilt fan means that they need a lot of electricity to operate, and fan convection heaters are a poor choice for heating large spaces. They are best suited for delivering quick heat.

The most serious disadvantage of fan convection heaters is that they are prone to overheating, especially when the element accumulates a covering of dust. Higher quality fan convection heaters contain inbuilt safety cut out switches, and these are worth the extra cost.