WASHINGTON — Over the past 20 years, the use of air conditioning has increased in all regions of the United States, but this increase has been most pronounced in the South, according to a new report from the U.S. Energy Information Administration (EIA). Since 1993, electricity consumed for air conditioning in the South has increased 43 percent and now accounts for 21 percent of all electricity consumption in the region. Nationally, electricity consumed for air conditioning has increased 39 percent since 1993, but only accounts for 14 percent of all electricity consumed. Several factors are responsible for this increase, including population growth, increased use of air conditioning, especially central air conditioning, and larger home size.

Between 1993 and 2009, the South added the most housing units, up 8.6 million units. Air conditioning has been widespread throughout most of the South for many years, but many households in the South have shifted from room air conditioning to central air conditioning, notes the report. In 1993, when 89 percent of households in the South used air conditioning, only 65 percent of households used central air conditioning while 27 percent used room air conditioning (window or wall units). By 2009, 96 percent of households in the South used air conditioning and 82 percent of households used central air conditioning, while only 15 percent of households used room air conditioning (1 percent of households used both central and room air conditioning in 2009, down from 3 percent in 1993).