11
Soft woods
Hard woods
• Douglas Fir
• Oak
• Pine
• Maple
• Spruce
• Apple
• Cedar
• Birch
• Poplar
• Aspen
• Alder
C. Fuel
1. Hardwood vs. Softwood
Your fireplace’s performance depends on the quality of
the firewood you use. One species of wood varies very
little to the other in terms of energy content. All sea
-
soned wood contains about 8,000 BTU’s per pound.
Hardwoods have a greater density than softwoods; a
piece of hardwood will contain about 60% more BTU’s
than an equal size piece of softwood. A cord of sea
-
soned oak (hardwood) would contain about 60% more
potential energy than a cord of seasoned pine (soft
-
wood).
Most softwoods are coniferous. These are trees with
needle-like leaves that stay green all year and carry
their seeds exposed in a cone. Examples of conifer
-
ous trees are Douglas fir, pine, spruce and cedar. Soft
-
woods, being more porous, require less time to dry,
burn faster and are easier to ignite than hardwoods.
Hardwoods are deciduous trees, broadleaf trees that
lose their leaves in the fall. Their seeds are usually
found within a protective pod or enclosure. Some ex
-
amples of deciduous trees are oak, maple, apple, and
birch. However, it should be noted that there are some
deciduous trees that are definitely not considered hard
-
woods such as poplar, aspen and alder. Hardwoods
require more time to season, burn slower and are usu
-
ally harder to ignite than softwoods. Obviously, you will
use the type of wood that is most readily available in
your area. However, if at all possible the best arrange
-
ment is to have a mix of softwood and hardwood. This
way you can use the softwood for starting the fire, giv
-
ing off quick heat to bring the fireplace up to operating
temperature. Add the hardwood for slow, even heat and
longer burn time.
WARNING! For use with solid wood fuel only.
Other fuels may overfire and generate poisonous gases (i.e.
carbon monoxide).
2. Moisture content
The majority of the problems fireplace owners expe
-
rience are caused by trying to burn wet, unseasoned
wood. Freshly cut wood can be as much water as it is
wood, having a moisture content of around 50%. Imag
-
ine a wooden bucket that weighs about 8 pounds. Fill it
with a gallon of water, put it in the firebox and try to burn
it. This sounds ridiculous but that is exactly what you
are doing if you burn unseasoned wood. Dead wood
lying on the forest floor should be considered wet, and
requires full seasoning time. Standing dead wood can
be considered to be about two-thirds seasoned, if cut at
the dry time of the year.
Burning wet, unseasoned wood will produce less heat
output because it requires energy in the form of heat
to evaporate the water trapped inside. This is wasted
energy that should be used for heating your home. This
moisture evaporates in the form of steam which has
a cooling effect in your firebox and chimney system.
When combined with tar and other organic vapors from
burning wood it will form creosote which condenses in
the relatively cool firebox and chimney.
Even dry wood contains at least 15% moisture by
weight, and should be burned hot enough to keep the
chimney hot for as long as it takes to dry the wood out
- about one hour. To tell if wood is dry enough to burn,
check the ends of the logs. If there are cracks radiating
in all directions from the center, it is dry. If your wood
sizzles in the fire, even though the surface is dry, it may
not be fully cured.
WARNING! Risk of Fire!
•
DO NOT
burn wet or green wood.
• Wet, unseasoned wood can cause accumulation of
creosote.
Heat & Glo • Rutherford 50-B Owner’s Manual • 4059-702 • Rev N • 04/21
