One of the historic uses of wood was for heating. In recent years, however, most heating in the United States has come from other sources of energy, such as petroleum, gas, and electricity. The scientists in this study wondered if using wood for heating would save schools money compared to the way the schools are usually heated. Topics: Engineering and Forest Products, Wilderness, Applied Science, Biomass Heat Energy, Energy Efficiency, Forestry, Natural Gas Heating, Oil Heating.