How to Select Firewood
Firewood selection could possibly be a more important issue than you realize. If you choose the best firewood, you will save money, cut down on pollution, and prevent excessive amounts of flammable creosote from being deposited in your chimney, creating the heightened threat of a hazardous chimney fire. The presence of moisture is what chiefly determines the quality of firewood, and what type of fire you want is the primary criteria for choosing which of the two types of wood to burn.
Only burn seasoned firewood in your fireplace or wood stove. When firewood is seasoned, it has been through a process of drying out. Living trees that are cut down are bursting with moisture. “Moisture content” refers to the amount of water in a piece of wood. The way moisture content is defined is that it is the weight of the water inside of the wood divided by the weight of the wood. To get the percentage of moisture, multiply by 100. It is not unusual for the moisture in a log to weigh more than the log itself. According to experts, the moisture content of freshly cut logs ranges from 45% to more than 200%.
What does all of that moisture have to do with saving money? If you burn green firewood that contains 30% moisture or more, about half of the heat that would have heated your home with seasoned firewood instead goes up the chimney. Seasoned firewood has a moisture content of less than 20%, and the usual range of moisture in seasoned firewood is between 15% and 20%.
Excess moisture in the firewood changes the dynamics of the fire. Instead of the energy of the fire going toward heat that could offset utility costs for you in winter, the energy goes toward evaporating the moisture. The excess smoke created by unseasoned firewood not only burns up more of your woodpile due to less heat being provided, it creates a danger to your home. The combustion gases from green wood create a greater amount of flammable deposits of creosote in your flue lining, which can cause a very dangerous chimney fire.
Store firewood and allow it to have protection from rain as well as exposure to sun and wind for six months to a year, in order to season it. If you are buying firewood, it can be difficult to determine if the wood is seasoned, although sellers invariably claim it is. Here are two tips that could help:
Learn to identify seasoned wood. One test is to look at it and make sure the ends look dry and cracked. If you bang seasoned wood together, you hear a distinct “clunk,” and pieces of the log may break off.
You can purchase a moisture meter that is designed to measure the amount of moisture in logs, drywall, and other materials. The meter will indicate the moisture content of the logs.
Hardwoods and Softwoods
Trees/logs fall into two major categories: hardwoods and softwoods. Hardwood is much denser than softwood and will burn longer and hotter than softwoods, producing about twice the heat.
Hardwoods produce natural coals that generate heat even after the fire has gone out. Softwoods, on the other hand, burn quickly and leave behind very little ash but are also a big component in the formation of creosote, a sticky, flammable substance that can cause a dangerous chimney fire.
Examples of hardwoods are: Maple, oak, hickory, birch, cherry, ironwood, and hackberry. Examples of softwoods are: Spruce, fir, redwood, and cedar.
It’s never too soon to get started on getting your firewood seasoned. Be sure to contact our professional chimney sweep early for an inspection, as well, to be sure your chimney is ready for the next cold season.
Chimney Solutions, Inc.
1155 McFarland 400 Drive, Alpharetta GA 30004