What kind of firewood do I need for my tiny wood stove?

 

The best fuel for your stove is thoroughly dried hardwood with a moisture content of less than 20%.  A wood moisture meter can be purchased for less than $10, and is a great investment if you’re going to be buying firewood or curing your own.  Avoid burning wet wood in your stove. For wet wood to burn, the water must be driven off first, which consumes heat. Wet wood lowers the BTU output of the stove and cools combustion gases which can cause poor draft and creosote formation.

 

CURING FIREWOOD

 

To cure firewood, split it and stack it loosely in a sunny location, perpendicular to the prevailing wind.  Cover the top of the stack only to keep precipitation off of it. The sides need to be exposed to allow airflow.

 

Different types of wood require different curing times, but in general, firewood needs to cure for a minimum of six months before it’s used.  Ideally, most firewood should be seasoned for 18 to 24 months. Most firewood purchased in bulk has not been seasoned sufficiently for immediate use, so you’ll need to purchase it at least a year in advance.

 

Even if the wood dealer says that the wood has been drying for a year, you should examine it before using it.  Wood does not dry quickly until it is split and stacked. A tree that has been down for over a year might still be more than half water.  Look for cracking on the cut ends of logs and bark that is falling off as good indications that firewood is properly seasoned. Properly cured firewood will weigh less than wet wood, and will make a sound like bowling pins when knocked together.  Wet wood will be heavy for its size and make a dull thud when knocked together.

 

The best way to tell if wood is properly cured is to use an electronic wood moisture meter.  Split a log and take a measurement from the center of the newly cut surface, parallel to the grain.  Properly cured wood should read less than 20% moisture content. If the wood reads higher than 20%, it needs a few more months to cure.

 

MOVING FIREWOOD

 

Don’t move air-dried firewood across long distances—it can potentially transport invasive species.   Introducing a new wood boring insect can be devastating to local forests, so be mindful of your firewood source.  If possible, find firewood within 10 miles of where you’ll use it. Don’t travel more than 50 miles with air-dried firewood.  

 

If you must travel with firewood, look for bundles of firewood from the hardware store that are labeled “kiln dried.”  Firewood that has been heated in a kiln is usually safe to transport, since all the insects inside it have been killed.  Manufactured pressed wood logs or bricks are also safe to transport, and are a good option for long, clean-burning fires.

 

FORAGING FOR FIREWOOD

 

Downed wood that you found in the forest is not usually the ideal fuel for immediate use in your wood stove, but it can be used if necessary.  If no other fuel source is available, having the ability to heat your home and cook your food with found wood can be a literal lifesaver.

 

Tools for foraging include a small hand axe for chopping limbs and splitting logs, a sturdy firewood carry bag for carrying your fuel, a wood moisture meter, and a saw capable of cutting through a medium sized log.  An electric or gas chainsaw is very helpful, but a 21” or larger bow saw will work if you don’t mind the manual labor, and a human-powered saw may be most reliable in an emergency.

 

Learn to identify your local trees by their leaves and bark so that you can pick out desirable firewood.  Hardwoods like oak and maple are ideal for wood stove fuel. Softwoods have lower BTU content than hardwoods since they’re less dense, but they can also work well as stove fuel. Soft, sappy woods like pine should be avoided if possible, since they can cause excessive creosote formation.

 

Wood that has been down for a long period of time can still have a surprisingly high moisture content.  Look for downed wood that has been sitting for a long while, but isn’t rotten. Bark that is falling off is often a good sign that a piece of wood is worth investigating.  Sometimes a good piece of wood is rotten on the outside, but has a core of solid dry wood. Once you think you’ve found a good candidate, cut a log from it, and split the log.  Use a moisture meter on the freshly split surface to verify that the moisture content is 20% or lower. If the wood is dry, cut as many logs as you can carry back home.

 

Avoid using wet fuel if possible, but if you have no other choice, there are a few things you can do to improve your results.  Cut your driest fuel into kindling to get your fire going. Wet kindling will require several tries to start a fire. Cut your wet fuel into small pieces to make it easier to drive off the moisture, and put new logs in the fire before you need them, so they have time to dry out.  Understand that the heat output of your stove will be significantly reduced with wet fuel, and your chimney will fill with creosote much more quickly. Be sure to inspect your flue system frequently and sweep it as often as necessary to avoid significant creosote buildup.

 

ALTERNATE FUELS

 

Most wood stoves can be used to burn a variety of solid fuels aside from wood.  Anthracite coal and charcoal are often acceptable fuels for use in wood stoves. You can use hardwood pellets by adding a fireproof basket insert that fits inside the fire box.  

 

Unacceptable fuels for a wood stove stove include any liquid fuels, which could cause the stove or the flue to explode.  Do not burn plywood, OSB, or other wood products containing glue, since the burning glue can be toxic, and can cause hard to remove deposits inside the flue.  Don’t burn trash, leaves or pine needles. Newsprint can be used as tinder for starting fires, but don’t burn large quantities of paper in the stove.

 

If you’re going to burn coal, anthracite coal is best.  Bituminous coal will also burn, but it gives off a lot of soot which is bad for air quality, makes a mess on the roof, and will clog up the flue system fairly quickly.  If you must burn a dirty fuel like bituminous coal, be sure to inspect and clean the flue system frequently.

 

Coal burns very differently in the stove than wood.  Wood fires burn from the top, so tighten down the primary air once there is a good bed of coals, and keep the secondary air open for an efficient burn.  Coal fires burn from the bottom up, so keep the primary air open and close the secondary air to keep the fire fed with fresh air from the bottom.

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