SOLID FUEL HEATING
Different types of wood have different burning qualities. Wet or damp wood does not generate as much heat as dry wood. Too much heat is wasted drying off the moisture and if you buy wood by weight, you are paying for a water content of up to 50%.
Generally hardwoods give more heat per unit of volume, but soft woods are easier to light. In an open fire, however, softwoods such as pines tend to spit and spark.
Coal or Coke - may also be used in stoves or fireplaces, but they generally require a wood fire to start combustion. Briquettes made from coal dust or
brown coal are a good alternative, although the binding compounds and the sulphur content can produce unpleasant smells.
Paper Log Rolls -
Newspapers can be converted into a fuel using a paper log rolling machine. These rolls can be made quickly and easily.
Flues and Chimneys
Chimneys are an integral part of a building structure and made of brick or of self supporting construction. A flue is a smoke pipe which is an addition to a stove or heater and may pass through the roof or through a wall before rising above the eaves. A number of considerations must be given to both flues and chimneys.
It is desirable that rain does not enter the flue and this can be prevented by a cap at the outlet or by "dog legging" the vertical riser. A chimney or flue must create sufficient draught to allow the smoke to be drawn up and out. They may be affected by "downdraught" caused by the shape of its own roof or adjacent roofs.
Flues are usually made of metal, and often have horizontal connections. Smoke contains hydrogen and sulphur which are carried up when hot, but if allowed to cool too much can mix with condensed water vapour to form sulphuric acid, which could run down and damage flues.
Similarly, wood burning stoves can be affected by unburnt tar products condensing and running back, thereby forming a potential hazard.
For these reasons, care must be taken not to overcool the flue gas. It is preferable to keep flues as short as possible or use multiple skin flues.