Energy In Buildings:
Home and Work

Primary energy includes power derived from steam, oil, natural gas, and coal in addition to electricity.  The difference in lighting energy consumption in homes and in commercial buildings is significant. The planning process for constructing commercial buildings now generally includes detailed lighting designs. In the past, such planning often lumped the lighting design in with the overall electrical installation or handled by the architect, if there was a lighting design at all.

Today, trained professionals evaluate not only the optimum levels of illumination in various spaces, but also how lighting will affect the energy consumption of a building. Many local governments are adopting building codes that place an upper limit on the amount of energy a new commercial building can use per unit area of floor space. 

To read the chart above, a definition is needed. A common measurement of energy is the British Thermal Unit or BTU. A BTU is the quantity of heat needed to raise the temperature of one pound of water one degree Fahrenheit. "Quad" in the chart stands for one quadrillion BTUs, and is a measure often used in energy industries.

Chart by Lee R. Anderson, compiled from information in "DOE Core Databook," 7 June 1996, U.S. Department of Energy.