Oil filled heaters don’t actually burn oil. They use electricity to heat the oil that’s sealed inside their columns or fins. The heat from the oil is then transferred to the casing and to the air circulating the fins.

These heaters rely mainly on natural convection. They take longer to heat a room than fan-assisted heaters of similar capacity. If there’s not much air movement, the heat may not be distributed evenly, and horizontal temperature layers may form. This could leave you with cold feet. However, there are now more and more fan-assisted column electric fireplace heaters available, which may help overcome these problems.

Column heaters are particularly useful in rooms where they’ll be switched on for long periods of time or where they’ll operate unattended. The surfaces you’re likely to touch on a column heater don’t get as hot as on other types of electric heaters. These heaters draw cold air over an electric heating element. The warmed air then leaves the heater and rises towards the ceiling, while cooler air moves in to replace it.

Fan heaters usually have a fan which enhances the convection effect by forcing the warm air from the heater. When you use the fan, the room will heat up more quickly and evenly. Without it, the air is more likely to form horizontal temperature layers which could leave you with cold feet, particularly, if there’s not much movement in the room, for example, if you’re reading or watching TV.

The fan will break up these layers to a certain extent. However, it’s also noisy, so make sure the fan of convector heater can be switched off. These can supply heat almost instantaneously, but can usually only chase the chill from a relatively small area, the air around you or maybe a small room. There’ll always be some noise, as the fan can’t be switched off. While some models are whisper-quiet, fan heaters aren’t really the best choice for areas you want to heat over long periods of time.