U.S. Energy Information Administration
U.S. Energy Information Administration

Commercial buildings continue to get bigger and bigger—at least the bigger ones do, anyway.

According to the recently released 2012 preliminary results of the Commercial Buildings Energy Consumption Survey (CBECS) by the U.S. Energy Information Administration, the amount of commercial floorspace in the U.S. increased from 51 billion square feet in 1979 to 87.4 billion in 2012.

Much of that is simply due to more buildings being constructed, but the size of those buildings has also increased. Buildings constructed between 2000 and 2012 average 19,100 square feet, while buildings constructed during the prior decade average just 16,300 square feet.

U.S. commercial buildings totaled 5.6 million in 2012, a 14 percent increase since 2003. The size of those buildings, meanwhile, has increased 22 percent in the same span. In short, the growth in the amount of floorspace is outpacing the increase in the amount of buildings.

A notable variable, however is that much of the floorspace is used up by a small percentage of buildings.

Buildings that span more than 100,000 square feet, according to the survey, make up approximately just 2 percent of the building count but account for approximately 35 percent of the total floorspace. That explains why the median square feet per building has actually fluctuated anywhere from 5,200 square feet to 6,800 square feet from as far back as 1960 to 2012.

“Commercial buildings are often depicted showing a skyline of towering buildings,” the study reads. “However, the vast majority of commercial buildings are relatively small. Just less than half of buildings are 5,000 square feet in size or smaller, and nearly three-fourths are 10,000 square feet or smaller.”

Lodging buildings are the largest of the 15 categories the survey notes, averaging 37,400 square feet per building. Education is second with an average of 31,600 square feet and healthcare third at 26,500 square feet. Food service buildings are the smallest, averaging just 4,800 square feet per building.

Moreover, the differences in size don’t just vary dramatically by sector, as geographic location is also a significant indicator.

Buildings in the Northeast are, on average, 4,000 to 5,000 square feet larger than buildings in other regions, according to the survey. But because the South is the most populous of the four regions, it has the largest percentage of commercial buildings and commercial floorspace, taking up approximately 40 percent of both.

With the preliminary results out, CBECS data collection is currently in its second phase—the Energy Supplier Survey (ESS)—which will be available beginning in the spring of 2015. The ESS provides consumption and energy intensity estimates by building activity.