11
The quality of the firewood you burn can have a big effect on the overall performance and efficiency of
your furnace. Several factors that affect the burning characteristic of firewood are moisture, tree species
and size. It is important you understand and follow our guidelines when choosing wood as a fuel source.
Fresh cut wood will have a moisture content between 35 and 50 percent by weight. If you try to burn
wet wood it will not only be difficult to ignite, but will hiss and sizzle in the firebox. Burning wet wood
consumes energy that will normally be used to efficiently complete the combustion process. Properly
seasoned wood will ignite easily and burn efficiently. Hardwoods like oak and maple dry more slowly then
softer woods like spruce and poplar. Properly seasoned wood would have a moisture content of less then
20%. Firewood dries slowly and may take a full year or more to season.
Ways to tell if firewood is dry enough to burn:
• Test wood with a moisture meter
(Recommended)
Moisture meters can be purchased at a local
hardware store for around $25.
• Wood darkens with aging, from white or cream in color to yellow or gray.
• There are cracks in the end grain.
• Banging two pieces together dry wood sound hollow, wet wood sounds dull.
• Split a piece and if the fresh surface feels damp and cool, the wood is wet. If it feels dry and warm it is
seasoned.
• When you burn it, if it hisses, it is too wet.
Types of Wood:
Wood can be classified as softwood or hardwood. The pines, spruces and firs are common softwoods and the oaks,
elms, birches, and maples are the common hardwoods. Softwoods burn rapidly and are more resinous than the
hardwoods, therefore they will cause a greater creosote build-up. Hardwoods produce a long lasting fire with uniform
heat. Hardwoods are the most desirable and are used by the majority of wood burners.
Proper Wood Storage:
1. Cut the wood to the desired length. It should easily fit in your firebox.
2. Split your wood before stacking it. - Splitting the wood in advance of stacking it increases exposure to air, which
improves drying time.
3. Check the moisture content - Place the moisture meter tip into the longest side of a piece of split wood. (Goal is 20
% moisture content)
4. Stack your wood in alternate directions - Spacing is needed to provide better circulation and helps in the drying
process.
5. Store your wood off the ground - Store wood six inches or more off the ground to prevent moisture.
6. Cover wood, but leave the sides exposed - Use a trap or best option is to build a structure that has a roof. If using a
tarp make sure your sides are open so moisture is not trapped.
7. Properly seasoned wood could take up to 12 months or more.
Purchasing Wood:
A cord of wood is a ranked stack of logs 4’ x 4’ x 8’. Usually when you purchase firewood, it is sold by the “face cord”.
A face cord is ranked stack of logs 4 feet high, 16 inches deep and 8 feet long. Wood is sometimes sold by the ton.
A ton of dry hardwood is equivalent to approximately ½ full cord. Whenever possible it is best to burn hardwood that
has been split and air dried for one year.
GUIDE TO BURNING WOOD