Source: U.S. Energy Information Administration, Commercial Buildings Energy Consumption Survey (CBECS)

Increases in the size of commercial buildings have outpaced increases in the number of those buildings over the past decade, according to EIA's Commercial Buildings Energy Consumption Survey (CBECS). EIA's CBECS is the only nationally representative data collection for building characteristics and energy use in commercial buildings. Information about the commercial building stock in 2012 is now being released, and energy-use information is expected later this year.

CBECS estimates that there were 5.6 million commercial buildings in the United States in 2012, totaling 87 billion square feet of floorspace. This level represents a 14% increase in the number of buildings and a 21% increase in floorspace since 2003, the last year for which CBECS results are available.

Newer buildings tend to be larger than older buildings. The average size of buildings constructed before 1960 (26% of the commercial building stock) is 12,000 square feet; buildings constructed between 1960 and 1999 (55%) average 16,300 square feet; and buildings constructed in the 2000s (18%) average 19,000 square feet.

Average building size has increased within a few buildings types in particular, reflecting changes in consumers' needs and wants. Four building types showed a statistically significant increase in building size when comparing buildings built before 1960 with those constructed in the 2000s:

• Health care buildings are getting larger, most likely to meet the needs of a population whose average life expectancy continues to increase.
• The size of lodging buildings increases substantially across vintages. Growing numbers of both leisure and business travelers led to the construction of larger hotels.
• Retail (other than shopping mall) buildings—a subset of the mercantile category, which includes malls—are larger, likely a result of the trend toward big-box stores.
• Religious worship buildings are also larger, possibly attributable to a growing number of megachurches, which have become more popular in the United States over the past two decades.

Source: U.S. Energy Information Administration, 2012 Commercial Buildings Energy Consumption Survey

The South's share of new buildings exceeds its share of the U.S. population (the South comprises 37% of the population but 46% of new buildings). Almost half of all commercial buildings constructed since 2000 were built in the South, which experienced the fastest rate of population growth across all census regions over the 2000-2012 period. These new buildings are 32% larger than those constructed before 2000.

Source: U.S. Energy Information Administration, 2012 Commercial Buildings Energy Consumption Survey and U.S. Census Bureau, Population Division