The pellets (wood pellets) are transported to the combustion chamber by means of a worm wheel. Here an electric heating element ensures that the pellets ignite. The air that is required to achieve good combustion is drawn in by an electronically controlled fan from the room or from the outside air.
There are also heaters with a closed system. The oxygen is supplied from outside via an external air supply. The oxygen that the stove needs does not come from the same room, but from outside, for example: the ventilation in the room is therefore less important than with an open system. Moreover, the living climate in the room is more pleasant with such an external air supply.
For all fireplaces and stoves a distinction applies between an open combustion and a closed combustion system. For every type of combustion, whether it is wood or gas, oxygen is needed to make the combustion take place. Open combustion systems extract the required oxygen from the room itself, with closed combustion systems the oxygen is extracted from outside.