In the case of residential lighting, new types of light bulbs,
compact fluorescent lights or CFLs, are becoming popular.
Wikipedia says the following about CFLs. A compact fluorescent
lamp (CFL), also called compact fluorescent light, energy-saving
light, and compact fluorescent tube, is a fluorescent lamp
designed to replace an incandescent lamp; some types fit into
light fixtures formerly used for incandescent lamps. The lamps
use a tube which is curved or folded to fit into the space of an
incandescent bulb, and a compact electronic ballast in the base
of the lamp. Compared to general-service incandescent lamps
giving the same amount of visible light, CFLs use one-fifth to
one-third the electric power, and last eight to fifteen times
longer. A CFL has a higher purchase price than an incandescent
lamp, but can save over five times its purchase price in
electricity costs over the lamp's lifetime. Like all fluorescent
lamps, CFLs contain mercury, which complicates their disposal.
In many countries, government