Heaters with thermostats use far less electricity than heaters that are “always on”. The reason? Heaters with thermostats switch themselves off when the room reaches the desired temperature, and on again when the room starts to cool down. That saves you money!
Some examples of heating solutions with thermostats are reverse-cycle air-conditioners, oil-filled radiators, various types of central heating.
Some examples of energy and money wasting heating solutions are infra-red radiators (the ones with the red bars), and small fan heaters. These types of heaters are usually the cheapest to buy, but in the long run, they are the most expensive to run.