Maximize your wood-heating investment
Wood can be an inexpensive fuel source. Use these tips to make sure you get the biggest bang for your buck.
March 23, 2012 - Author: Bill Cook, Michigan State University Extension
It’s a romantic notion, sitting around a wood stove on a crisp autumn night, or a downright frigid January morning. Using wood to heat a home or business is also cheaper than just about anything else. But it takes some work. And, some homework.
If you don’t consider the time to process firewood and all the handling that’s involved, then wood is by far the least expensive fuel source. If you buy firewood that is already cut and split, then the costs need to be looked at more closely. Similarly, it would be wise to compare costs if you are considering a wood-pellet stove. Wood costs will usually trump any of the fossil fuels.
If you have a commercial or municipal operation and are considering a wood-chip heating and cooling system, then you’ve found the least expensive and most reliable alternative. But this idea is part of another story.
Firewood delivered in 8-foot lengths will run around $100 per cord for hardwood. In addition, you’ll probably need to buy a truckload, which can range from five cords to 13 cords depending on the hauler and the truck.
A standard cord is a stack of 8-foot sticks stacked 4-feet high and 4-feet wide. The actual volume of wood will vary with the size of the sticks. There are other definitions for cords, so buyer beware: know what you’re buying.
Most homes will require about five or six cords per winter, but that varies widely with the variety of homes. So, wood costs will be roughly $500-600, plus electricity to run any fans or push water. That’s about $11 per million BTUs. At $2.50/gallon, propane will run about $35 per million BTUs. Electricity may run around $65.
Wood looks good based on these loose estimates, but there’s more work to wood than for fossil fuels. The delivery truck must have room to move around. A load of eight-foot firewood needs to be cut, split, stacked, covered and dried. Equipment and space are needed. A considerable amount of sweat equity will be invested before the stove is filled. Some call this recreation.
Drying firewood is essential. It takes energy to drive water out of wood and that’s energy that will not be spent heating a house. Burning wet wood adds to incomplete combustion, reduces efficiency and increases residue inside a chimney. Looking for firewood in the fall, to burn in a few weeks, is looking for trouble.
Burning firewood also means having a safe burning environment and a well-maintained chimney. Every winter, people lose their homes due to poor wood burning design or burning practices. Inadequate fuel can also irritate neighbors. Thick smoke from improperly burning wood stoves contains particulates and emissions that can harm people with respiratory problems. It’s also just plain rude. Proper operation of even simple stove designs minimizes these issues.
Much has been said about the amount of energy in different species of wood. Energy content does vary somewhat, but water content and proper air control are, by far, the more important factors. For the northern Lake States, sugar maple is probably the best mix of energy content, ease of processing and availability. Oak is also quite good but it’s less available; therefore usually more expensive. Energy charts are easy to come by, but not all tree species are nice to work with or obtainable. The U.S. Department of Agriculture Forest Products Laboratory has the scoop on all these factors.
Lastly, firewood transport has been one of the more common vectors for exotic and invasive species. Examples include oak wilt, emerald ash borer, and gypsy moth. There are several other nasty species on the horizon. Be careful when buying or transporting firewood. It’s good to ask, in advance, where the wood is coming from and become aware of potential hazards. It’s also good to get wood processed and stacked as soon as possible.
Burning wood to heat homes is still a great idea, but doing it ‘right’ is becoming increasingly more important.
