The BTUs of Wood Vs. Fuel Oil

Wood BTUs vs. Home Heating Oil

• At 17 to 20 million BTUs, one cord of wood generates an output of BTUs equivalent to 150 to 200 gallons of home heating fuel oil. When you compare the difference in costs, a cord of wood can actually be competitive when compared to the cost per gallon for fuel oil. Wood is also more consistent in pricing than fuel oil. This might make wood worthy of consideration as an alternative or sole source of heating for a small room, such as a living room or family room with a fireplace or wood-burning stove.

Wood vs. Propane

• One gallon of propane generates 91,330 BTUs. To compare propane to wood, let's say that a home uses 50 million BTUs for heating over the course of a year. That home would require close to 548 gallons of propane for the year. If the home solely relied on wood, it would require around three cords of wood. Check out propane costs and cord costs in your area to do a cost comparison.

Wood vs. Gasoline Fuels

• While there are no wood-burning vehicles on the horizon (at least for now), it is still interesting to compare how wood and gasoline fuels differ in BTU output. Since a pound of wood generates 6,200 to 7,500 BTUs, the scales tip in deference to gasoline for vehicles. A pound of diesel fuel generates 19,300 BTUs, and a pound of gasoline (such as the type you use in your car) generates 20,400 BTUs. This means that fuels for vehicles generate three to four times the amount of BTUs as wood. Gasoline has little to fear about wood becoming a chief competitor.

Wood BTUs by Species

• Species of wood that rank highest on the BTU scale are hard maple at 29.7 million BTUs per cord, black birch and gray birch at 26.8 million BTUs, shagbark hickory at 27.5 million BTUs, and white oak at 26.5 million BTUs. Lowest on the scale is cottonwood, at only 12.2 million BTUs per cord. However, there can be variance in the BTU output based on the wood's moisture content, and on how well the wood has been seasoned that is selected for burning.

Wood BTU Considerations

• Wood heats at various temperatures as it burns and undergoes a natural combustion process before it generates heat that you can feel. In the first phase, it heats up internally to 212 degrees Fahrenheit to evaporate any moisture still inside the wood log, without emitting any heat into a room. After that, it heats up to 575 degrees Fahrenheit to break down and convert its internal components into gases. Finally, after reaching 575 degrees, it begins to emit heat, and continues to do so, reaching temperatures as high as 1,100 degrees Fahrenheit. During this phase, wood disburses 40 to 60 percent of its energy, and converts into charcoal.