Civic Communications Specialist
2400 S. Scenic Ave.
Springfield, MO 65807
September 9, 2011
Wood as a Heating Fuel a Good
Choice for Many, But Plan Ahead
PINEVILLE, Mo. Higher costs in heating fuel prices and electricity has many homeowners dusting off old wood stoves and researching the latest wood stove technology.
"If you are thinking about using wood for heat you'll also want to spend some time contemplating where you are going to get your firewood," said John Hobbs, agriculture and rural development specialist, University of Missouri Extension. "Wood is a plentiful and accessible fuel for many Missourians and for those who think "green," it is a renewable resource as compared to coal or oil."
As a rule of thumb, a cord of air-dry hardwood fuel yields about the same usable heat as 250 gallons of propane (LP), a ton of hard coal, or about 6500 kilowatt hours of electricity.
By comparing the cost of other fuels with cordwood, Hobbs says a person can figure out the savings they will realize by burning wood to heat their home.
"Don't expect to go out in the backyard when the weather turns cold to cut down a few trees to saw up and throw into the new stove. It takes time to cure and dry firewood. Burning green firewood is very inefficient, and it can be unsafe," said Hobbs.
The moisture content of green wood averages 60 to 80 percent of the total weight of a cord of firewood, depending on when it was cut.
"Evaporating all that water in your stove will use as much as 15 percent of the potential heat in your firewood, so you are better off letting nature do it for you by air-drying your wood before you burn it," said Hobbs.
Burning green wood also promotes a buildup of creosote in the chimney, increasing the risk of a dangerous chimney fire.
It will take about six months to air-dry a cord of cut and split wood to 30 percent moisture content and nine months to reach 20 percent moisture content.
"If you haven't started cutting and splitting your wood pile, you won't catch up before cold weather arrives this fall. That means you'll probably need to buy dry firewood this year and plan on using any wood you cut now during the next heating season," said Hobbs.
What is the best wood to burn? Not all firewood is created equal according to Hobbs.
"Some species of trees are denser and therefore able to produce much more heat per cord of wood," said Hobbs.
Following are heat values in million BTU's (per cord for various species of tree. The higher the BTU value, the more potential heat generated.
Good wood choices in Missouri include: Ash, Green 23.6; Elm, American 20.1; Hackberry 21.6; Red Oak 25.3; Locust, Black 28.1; Hickory 29.1; Maple, Silver 20.8; Mulberry 25.3; Oak, Post 27.0; Sycamore 20.7; and Osage Orange (Hedge) 30.7.
"Heating a house with wood, is relatively clean and economically beneficial. That burning wood is physically healthful, and that experiencing it is comforting to the body and soothing to the spirit," said Hobbs.
For more information, obtain a copy of MU Guide G5450 "Wood Fuel for Heating" at your nearest county extension center on online at extension.missouri.edu`.
Source: John Hobbs, (417) 223-4775