Energy Conservation

Energy use in the United States

In 2010, the Department of Energy (DOE) estimated that the United States consumed 98 quads (quadrillion British thermal units). The operation of all buildings directly consumed approximately 41% of that total. Residential buildings were responsible for about 55% of the buildings total, or 23% of the total U.S. consumption. It is important to note that these values are based on primary energy use. In other words, the energy losses associated with electricity power generation and transmission are included and assigned accordingly to each end-use sector. Much of the primary energy used is lost during conversion. According to Lawrence Livermore National Laboratory research of energy flows, almost 60% of the energy consumed in the United States is rejected through power plant generation and transmission losses, venting losses of heating plants, and tailpipe emissions. This highlights a very large potential for energy efficiency improvements in all sectors.

There is another significant component of building energy consumption. Building-related materials, goods, and services also use substantial quantities of energy for extraction, manufacture, transportation, and construction. While this number is buried deep within the industrial and transportation sectors, it is estimated to be approximately 7% of the industrial and transportation sectors. If these are added to the buildings’ operations component, it is estimated to raise the total energy fraction of the buildings sector to almost 49%, according to the advocacy group Architecture 2030. That puts the total residential sector energy budget at slightly more than 27% of the total U.S. energy budget. And many sources suggest that energy use by the buildings sector is predicted to grow faster than both transportation and industrial consumption. This would suggest that further attention and importance will be focused on energy conservation in our homes.

Despite several decades of energy conservation improvements, the energy use in residential buildings has stayed virtually the same; however, there are a couple of caveats. First, total housing units went from 76.6 million in 1978 to 111.1 million in 2005, so energy consumption per housing unit did decrease over that period. While the total energy for space heating has been reduced from 6.96 to 4.30 quads between 1978 and 2005, air-conditioning has increased from 0.32 to 0.88 quads during that same period. This is presumably due to both the population shift to warmer climates and an increase in the market penetration of air conditioners. Even more telling is the increase in appliances and electronics, which has increased dramatically from 1.77 quads in 1978 to 3.25 quads in 2005.

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