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Commercial Buildings Energy Consumption Survey (CBECS)

Energy Characteristics and Energy Consumed in Large Hospital Buildings in the United States in 2007 Main Report | Methodology | FAQ | List of Tables

CBECS 2007 - Release date: August 17, 2012

Hospitals consume large amounts of energy because of how they are run and the many people that use them. They are open 24 hours a day; thousands of employees, patients, and visitors occupy the buildings daily; and sophisticated heating, ventilation, and air conditioning (HVAC) systems control the temperatures and air flow. In addition, many energy intensive activities occur in these buildings: laundry, medical and lab equipment use, sterilization, computer and server use, food service, and refrigeration.

The 2003 Commercial Building Energy Consumption Survey (CBECS) data showed that large hospitals (greater than 200,000 square feet) accounted for less than 1 percent of all commercial buildings and 2 percent of commercial floorspace, but consumed 4.3 percent of the total delivered energy used by the commercial sector in 2003 1. Data from the 2007 CBECS show that the major fuels (electricity, natural gas, fuel oil, and district heat) consumed by large hospitals totaled 458 trillion Btu, which is 5.5 percent of the total delivered energy used by the commercial sector in 2007.

Large hospital buildings comprised 1.96 billion square feet of floorspace

In 2007, there were approximately 3,040 large hospital buildings in the United States. By Census Region, 26 percent of them were in the Northeast, 19 percent were in the Midwest, 39 percent were in the South, and 16 percent were in the West. The large hospitals comprised 1.96 billion square feet of floorspace, 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.

In large hospitals, natural gas was the most used space heating and water heating fuel

Large hospital buildings in 2007 consumed a total of 458 trillion Btu in major fuels: 208 trillion Btu of natural gas, 194 trillion Btu of electricity, 6 trillion Btu of fuel oil, and 49 trillion Btu of district heat 2. The major fuel intensity was 234,100 Btu per square foot of floorspace. As shown in Figure 1, natural gas was the most common main space heating fuel, used by 74 percent of the buildings, followed by district heat, 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. Cooking was reported in 95 percent of the buildings, with natural gas and electricity the most common cooking fuels. Because of their need for a secure, reliable source of electricity, almost all large hospitals (95 percent) generated electricity, primarily for emergency back-up generation. Fuel oil was by far the most common generation fuel.

Energy management and conservation reported in high percentages

Not surprisingly, most of these energy-intensive buildings had energy management and conservation plans in place, and used technology and products to save energy. As shown in Figure 2, nearly all had regular maintenance and scheduled repair for the HVAC system. In 88 percent of the buildings, all or a portion of the windows were multi-layer glass and 76 percent of them used an economizer cycle, which pulls in outside air for cooling.

About 93 percent of them used one or more daylighting 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). About 90 percent of them used compact fluorescent bulbs (CFLs), and 40 percent of them used light-emitting diode lights (LEDs) to light 11 percent and 2 percent of the total lit building floorspace in all large hospitals, respectively.

Water data collected for the first time; large hospitals used 132.5 billion gallons in 2007

For the first time in its 30 year history, the CBECS collected data on water use. See the accompanying water methodology report for details. Large hospital buildings in the United States 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. The overall consumption per square foot was 67.7 gallons. The Midwest, South, and West Census regions had similar water-use intensity: 76.0, 68.1, and 72.7 gallons per square foot, respectively. The Northeast had a lower intensity of 55.5 gallons per square foot. In addition to the typical uses of water in commercial buildings, these buildings reported other intensive uses of water in high percentages. More than 99 percent of them used sterilizers or autoclaves, which use water to sterilize containers, medical instruments, surgical tools, and trays. Irrigation systems to water outdoor landscapes were found in 75% of the hospitals, while 88 percent used large amounts of hot water for commercial dishwashing, laundry, heated pools, steam rooms, whirlpools, or showers. On-site laundry facilities were reported for 17 percent of the buildings.


1 Total delivered energy used by the commercial sector in 2003 and 2007 were calculated using Total Primary and Total Electricity Retail Sales in Table 2.1c of the 2010 Annual Energy Review (AER). Delivered energy does not include primary energy lost in the generation and transmission of electricity.

2 District heat:  Steam or hot water from an outside source used as an energy source in a building. The steam or hot water is produced in a central plant and piped into the building. The district heat may be purchased from a utility or provided by a physical plant in a separate building that is part of the same facility (for example, a hospital complex or university).

Specific questions on this product may be directed to:

Joelle Michaels