Instruction Manual

Page 12
500IH-I05-020320
double of that of a square metre of softwood. This means that the same volume
of hardwood will provide you with more fuel to burn than an equal amount of
softwood, simply because it contains more substance.
(N.B. The price of hardwood will normally not be double that of softwood,
because it took the same amount of labour to prepare. So, if a trailer full of
hardwood costs more than the same size trailer full of softwood, the more
expensive option may well be the most economical.)
The other advantage of good hard firewoods are that the cooker does not need
to be fed as often and the charcoal-beds made by the glowing wood may burn
more easily overnight.
However, the ideal situation would be to have a store of both hard and soft
woods, because the softer woods also have distinct advantages. They light more
easily than the slower burning hardwoods and if the softwoods are dry, they
create a hotter, more intense fire. The draught created by the hotter fire moves
the air up the chimney faster.
After reading the notes opposite about the burning process, you will understand
that means less pollution in the form of smoke and less creosote condensation
in your chimney.
The denser hardwoods tend to smoulder more easily when the fire is first lit, so
their flue gas temperature will be much cooler.
Because softwoods like pine and larch contain a lot of resins and pitch, a popular
misconception is that they will fur up the chimney with creosote more easily
than a hardwood like oak. This is not necessarily true at all. It is not the pitch
that is the problem, it's the water IN the pitch. Once the water in the wood has
evaporated, that pitch becomes high octane fuel. When dry, softwoods burn
extremely hot.
There is also the matter of seasoning to be considered. When you buy wood, it
will usually have been cut in the winter of the year you buy it. Hard woods tend
to take longer than softwoods to fully dry out.
Softwoods cut in the previous winter should, with proper storage, be ready to
burn the next autumn, whereas many hardwoods may take a bit longer than
that. Oak, for example, is very slow to dry out and ideally left for two years. It is
also possible to purchase pre seasoned wood or kiln dried wood.