Kerosene heaters work much like kerosene lamps, with a holding tank, wick and chimney. Most have a battery-operated igniter that heats the wick. Once the heater is warm, it produces few fumes or odors.
The wick uses capillary motion to draw the fuel from the tank to its top. Once the fuel reaches the top of the burning wick it evaporates to create a flammable gas. In a properly burning stove, the process consumes very little of the wick.
Kerosene heater wicks are made of either fiberglass or cotton. Fiberglass wicks are maintained by burning the heater dry, or allowing consumption of all the fuel in the tank. Since this creates more fumes, most owners move the heater outside for the wick cleaning process. Cotton wicks should never burn dry, but owners maintain them by wiping them clean with a paper towel.
Kerosene heaters do not vent to the outside, so they release all the byproducts of combustion in the area they heat. If the user does not adjust the flame properly, incomplete combustion produces carbon monoxide, an odorless gas that is deadly. The surface of the heater becomes extremely hot, creating a fire and burn hazard. Owners must allow the unit to cool completely before refueling for safe operation.