Fluorescents are more energy efficient overall. To
commence with, fluorescent lights have a much longer
life than incandescent lights--the fluorescent tube
lasts many thousands of hours and its fixture lasts
tens of thousands of hours. So the small amount of energy
spent building an incandescent bulb is deceptive--you
have to build a lot of those bulbs to equal the value
of one fluorescent system.
Second, although there is considerable energy obsessive
in manufacturing the complicated components of a fluorescent
lamp, it's unlikely to more than a few kilowatt-hours--the
equivalent of the extra energy a 100 watt incandescent
light uses up in a week or so of typical operation.
So it may take a week or two to recover the energy cost
of building the fluorescent light, but after that the
energy reserves continue to ensue for years and years.
