Energy Efficiency

Approximately one-third of all the energy used in the United States goes to heat, cool, and light buildings. A number of technologies have been developed that improve the efficiency with which energy is used in buildings. Some of these changes are simple; higher grades of insulation are used in construction, and air leaks are plugged. Both of these changes reduce the amount of heated or air-conditioned air (depending on the season) lost from the building to the outside environment.

Other improvements involve the development of more efficient appliances and construction products. For example, the typical gas furnace in use in residential and commercial buildings in the 1970s was about 63% efficient. Today, gas furnaces with efficiencies of 97% are readily available and affordable. Double-glazed windows with improved insulating properties have also been developed. Such windows can save more than 10% of the energy lost by a building in a year.

Buildings can also be designed to save energy. For example, they can be oriented on a lot to take advantage of solar heating or cooling. Many commercial structures also have computerized systems that automatically adjust heating and cooling schedules to provide a comfortable environment for occupants only when and in portions of the building that are occupied.

Entirely new technologies can be used also. For example, many buildings now depend exclusively on more efficient fluorescent lighting systems than on less efficient incandescent lights. In some situations, this single change can produce a greater savings in energy use than any other modification. The increasing use of solar cells is another example of a new kind of technology that has the potential for making room and water heating much more efficient.