 This feature was much more common in oil heaters than in the cheaper fan heaters until recently; thus many older oil heaters will be cheaper and more efficient to run than their contemporary fan heaters that lack the thermostat.Typical oil heaters range in power consumption/output from 300 to 2400 watts, and their length and number of columns is roughly proportional to their power rating.A 2400 watt oil heater is usually approximately 1 meter (3.3 feet) in length.