Large hospitals are big consumers of energy. Just how much is the subject of new results from the U.S. Energy Information Administration’s (EIA) Commercial Buildings Energy Consumption Survey (CBECS).
The CBECS shows that the major fuels – electricity, natural gas, fuel oil and district heat – consumed by large hospitals (greater than 200,000 square feet) totaled 458 trillion British thermal units (Btu) – 5.5 percent of the total delivered energy by the commercial sector in 2007. Total delivered energy to the 3,040 large hospitals in the U.S. in 2007 is up from 4.3 percent in 2003.
“We didn’t see any surprises in the data released, which is good and bad,” said Alan Swenson, energy analyst at the EIA. “Bad that no major changes were found in energy use but good in that we believe it shows our data is accurate.”
Swenson pointed out that hospitals consume large amounts of energy because of how they are run and operated – they are open 24 hours a day, have thousands of employees, patients and visitors, and they use sophisticated energy-intensive activities and machinery.
The 3,040 large hospitals in the country in 2007 comprised 1.96 billion square feet of floor space, with an average of 644,300 square feet per building. A total of 3.3 million employees worked in those buildings, with an average of 586 square feet per employee. The total licensed bed capacity was 915,000, with an average of 2,140 square feet per licensed bed, according to the data.
Natural gas was the most common main space heating fuel, used by 74 percent of the buildings, followed by district heat at 20 percent. All buildings had air conditioning and nearly all, 92 percent, used electricity to power air conditioning equipment. Water heating was also used in all buildings and had fuel use percentages similar to space heating: 74 percent used natural gas and 18 percent used district heat, according to CEBCS’ data.
Many hospitals are actively trying to reduce energy consumption, EIA noted in its report on the survey. Most of these energy-intensive buildings had energy management and conservation plans in place, and used technology and products to save energy. In 88 percent of the buildings, all or a portion of the windows were multilayer glass, and 76 percent of them used an economizer cycle, which pulls in outside air for cooling.
In addition, about 93 percent of the hospitals used one or more day lighting or lighting conservation features, including tinted window glass (80 percent), reflective window glass (39 percent), external overhangs or awnings (47 percent), skylights or atriums designed to provide light (57 percent), automatic controls or sensors that increase or reduce lighting in response to the level of natural light (14 percent), and occupancy sensors that reduce lighting when rooms are unoccupied (46 percent).
For the first time, CBECS collected data on water use by large hospitals and found that they consumed about 133 billion gallons of water in 2007, totaling $615 million in water expenditures, with an average of 43.6 million gallons and $202,200 per building.