Portable radiators are powered by electricity and they use an oil filled body that is heated by an element which warms up the liquid.
These radiators usually have fins and work like convection radiators, but with the added advantage of being mobile. They will normally plug into any mains electricity socket and a short cable allows them to be positioned for optimum warms. This makes them ideal for short bursts of heat in smaller rooms, or to supplement warmth in a larger room on a cool day.
Nearly all portable radiators have thermostatic controls and it is usually possible to set their temperature quite accurately. The disadvantage to their thermostatic operation is that, unlike a central heating system, the thermostat is houses on the radiator itself (i.e. in the hottest part of the room). This can frequently lead to the radiator turning itself off when the immediate area around it is warm, but the outer parts of the room are not. This can of course be compensated for by increasing the heat setting.
The more expensive mobile radiator models often have timers in addition to their thermostats. This extra function enables the radiator to be set to switch on and off at specific predetermined intervals. This makes them ideal for night time and early morning use.
The biggest downside to mobile radiators is the way in which they are powered and consume energy. Oil filled electric powered radiators can be expensive to run and, if used as a primary heating source, they can be far from economic.
For this reason, these radiators are best suited to supplemental heating use, short term heating, or use as an emergency heater in the event of the main heating system failing.