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major appliances and other uses in the residential and commercial segments of the buildings sector.

In the residential and commercial building sectors, electricity efficiency technologies include such measures as

• more efficient fluorescent lamps, high-frequency ballasts, reflectors, and occupancy and daylight sensors that, together, can save up to 84 percent of lighting energy in commercial buildings while maintaining the same level of useful light (Lovins, 1986);

• superefficient appliances that, through a variety of complementary technologies, achieve the same level of performance while consuming far less energy; and

• building shell measures such as insulation, trees that shade windows, white roof and pavement surfaces that reflect sunlight, and heat-reflective windows that retain heat in winter and deflect it in summer.

White Surfaces and Vegetation

Planting vegetation and painting roof and road surfaces white can save approximately 50 BkWh/hr of the total U.S. air conditioning use of 200 BkWh/yr. Of the 50 BkWh/yr, about 25 BkWh/yr are direct savings from decreased air conditioning needs in buildings that have light-colored roofs and are shaded by properly placed deciduous trees. Indirect savings of another 25 BkWh/yr are realized once vegetation, light-colored roofs, and light-colored roadways are in place, cooling "urban heat islands" in the summer. "Urban heat islands" is the term used by meteorologists to describe the fact that in summer most cities are 2° to 5°C hotter than their surroundings. The cause is solar heat absorbed by dark surfaces, and the removal of trees that would have cooled the air by evapotranspiration. The total savings including indirect savings from the cooler cities could equal 50 BkWh/yr (Akbari et al., 1990).5

Electrical Appliances

Residential and Commercial Lighting

Lighting is the largest end use in the commercial sector (257.4 BkWh/yr in 1986) (U.S. Department of Energy, 1989a) and about 11 percent of all residential electricity (90.4 BkWh/yr in 1986) (U.S. Department of Energy, 1989a). The efficiency of existing lighting can be improved through the use of compact fluorescent lamps (CFLs). Today's efficient CFLs have long life, good color, and reduced maintenance cost. Two types of CFLs are available: one with separate ballast and the other with "integrated" built-in ballast. Each can fit into a standard light socket (Lawrence Berkeley Laboratory, 1990).

Because CFLs are 4 times as efficient as incandescent bulb and last a