Why Electric? Compared with other forms of heating, electric is cheap and easy to install, clean, efficient, faster to heat up and cool down, but the running costs can be higher, although at the time of writing, gas costs are rising faster than electric. Many people with gas or other forms of central heating use electric heating as extra top up heating.
No matter what kind of heater you have the running costs depend on the number of kilowatts the heater uses. At the time of writing, a 1kW heater on for an hour costs approx. 8p in electricity. A 2kW heater costs twice as much, a ½ kW (500W) half as much and so on. However, many heaters have a thermostat, which switches the heater off when the room reaches a temperature which you set. When the heater is off, it uses no or hardly any electricity. It is therefore better to get a heater with a thermostat unless you will only be using it for short periods or it has a very low wattage. As stated above heaters with thermostats can be set to maintain the room at whatever temperature is comfortable for you. If your heater does not have a stat., you can still buy a plug in stat. which has the same effect. Most thermostats have a 'frost-watch' setting, which only switches on when the temperature gets to freezing. Useful to leave on to prevent burst pipes if you are going away, or to be left in the loft. Some heaters also have built in timers, which can be set to switch the heater on and off at pre-set times (useful for waking up to a warm house, or coming in to one when you have been out). Similarly if your heater does not have one you can buy a plug in timer.
For a discussion of electrical heating see: http://ezinearticles.com/?Electrical-Heating-in-the-Home&id=731771