To answer this, you need to understand the difference between an electric "thermal inertia" radiator which is specifically designed to operate on a minimum amount of electricity and a standard electric radiator which is essentially a central heating radiator filled with fluid and inserted with a heating element.
The picture above, is a thermal inertia radiator from Elnur. Thermal inertia is the quantity of heat that a body can store and the speed at which it can transmit and absorb heat. Built using cutting edge materials and thermostatic control, thermal inertia radiators warm the room quickly and continue to emit heat when turned off, the result being significant reductions in running costs.
By contrast, the picture below is a standard central heating radiator from Reina adapted for use as an electric radiator by filling it with fluid and adding a heating element to allow it heat like water in a kettle. This type of radiator is clearly going to cost more to run but a lower purchase price can make it an attractive alternative for use in areas where occasional or intermittent heating is required.
In conclusion, when running costs are the decisive factor, electric thermal inertia radiators are the obvious choice. However, if running costs aren't the deciding factor, a standard electric radiator is the cheaper option and will do the same job.
At Electric Heat Warehouse, we have both types and happy to discuss which fits best for your project. Feel free to call us on 0330 2232604