Firewood is an area where you can have great influence over how well your system performs and how enjoyable your experience will be. Quality, well seasoned firewood will help your wood stove or fireplace burn cleaner and more efficiently, while green or wet wood can cause smoking problems, odor problems, rapid creosote buildup and possibly even dangerous chimney fires.
A few minutes spent understanding firewood will be time well spent, so please read on for general background information, as well as how to buy wood and store wood.
All firewood contains water. Freshly cut wood can be up to 45% water!, while well seasoned firewood generally has a 20-25% moisture content. Well seasoned firewood is easier to start, produces more heat, and burns cleaner. The important thing to remember is that the water must be gone before the wood will burn. If your wood is cut 6 months to a year in advance and properly stored, the sun and wind will do the job for free. If you try to burn green wood, the heat produced by combustion must dry the wood before it will burn, using up a large percentage of the available energy in the process. This results in less heat delivered to your home, and literally gallons of acidic water in the form of creosote deposited in your chimney.
Wood is composed of bundles of microscopic tubes that were used to transport water from the roots of the tree to the leaves. These tubes will stay full of water for years even after a tree is dead. This is why it is so important to have your firewood cut to length for 6 months or more before you burn it, it gives this water a chance to evaporate since the tube ends are finally open and the water only has to migrate a foot or two to escape. Splitting the wood helps too by exposing more surface area to the sun and wind, but cutting the wood to shorter lengths is of primary importance.
There are a few things you can look for to see if the wood you intend to purchase is seasoned or not. Well seasoned firewood generally has darkened ends with cracks or splits visible, it is relatively lightweight, and makes a clear "clunk" when two pieces are beat together. Green wood on the other hand is very heavy, the ends look fresher, and it tends to make a dull "thud" when struck. These clues can fool you however, and by far the best way to be sure you have good wood when you need it is to buy your wood the spring before you intend to burn it and store it properly.
Watch this short video from the EPA to learn more:
Even well seasoned firewood can be ruined by bad storage. Exposed to constant rain or covered in snow, wood will reabsorb large amounts of water, making it unfit to burn and causing it to rot before it can be used. Wood should be stored off the ground if possible and protected from excess moisture when weather threatens.
The ideal situation is a wood shed, where there is a roof but open or loose sides for plenty of air circulation to promote drying. Next best would be to keep the wood pile in a sunny location and cover it on rainy or snowy days, being sure to remove the covering during fair weather to allow air movement and to avoid trapping ground moisture under the covering. Also don't forget that your woodpile also looks like heaven to termites, so it's best to only keep a week or so worth of wood near the house in easy reach. With proper storage you can turn even the greenest wood into great firewood in 6 months or a year, and it can be expected to last 3 or 4 years if necessary.
Firewood is generally sold by volume, the most common measure being the cord. Other terms often employed are face cord, rick, or often just a truckload. A standard cord of firewood is 128 cubic feet of wood, generally measured as a pile 8 feet long by 4 feet tall by 4 feet deep. A face cord is also 8 feet long by 4 feet tall, but it is only as deep as the wood is cut, so a face cord of 16" wood actually is only 1/3 of a cord, 24" wood yields 1/2 of a cord, and so on.
Webster defines a rick simply as a pile, and truck sizes obviously vary tremendously, so it is very important that you get all of this straight with the seller before agreeing on a price; there is much room for misunderstanding. It is best to have your wood storage area set up in standard 4 or 8 foot increments, pay the wood seller the extra few dollars often charged to stack the wood, and warn him before he arrives that you will cheerfully pay only when the wood actually measures up to an agreed upon amount.
Another thought concerning getting what you pay for is that although firewood is usually sold by volume, heat production is dependent on weight. Pound for pound, all wood has approximately the same BTU content, but a cord of seasoned hardwood weighs about twice as much as the same volume of softwood, and consequently contains almost twice as much potential heat. If the wood you are buying is not all hardwood, consider offering a little less in payment.
Top Firewood Tips
It is far more important that the fuel be dry as compared to the species.
Do not burn any construction scraps of treated or painted wood, especially treated wood from decks or landscaping ties. The chemicals used can release dangerous amounts of arsenic and other very toxic compounds into your house.
If the "seasoned wood" you bought turned out to be pretty green and you elected to try to burn it anyway, be sure to have the chimney checked more often than usual, you may build up creosote very quickly. You don't have to burn only premium hardwoods. Less dense woods like elm and even soft maple are abundant and make fine firewood as long as you're willing to make a few extra trips to the woodpile.
If you have access to a variety of species, learn to manage your woodpile. Save the more dense fuel for the coldest months and use the "lighter" wood for kindling fires and during the spring or fall when you don't need as much heat.
Many people also have questions about burning artificial logs. Convenience is their strong suit and in general they are fine when time is an issue and you want a quick fire without all the muss and fuss of natural firewood. Usually they should be burned only one at a time and only in an open fireplace. One should be careful about poking them and moving them around once they are burning since they may break up and the fire may get a bit out of control. Be sure to carefully read the directions on the package.
More firewood tips from the EPA: