Each differs greatly, so we'll illuminate you further....
According to the American Lighting Association, LEDs are the most expensive but last longest and are also mercury free, so they are the way to go.They are going into all parts of the home, not just in fixtures and lamps. The evolution of the LED, says Joe Rey-Barreau, architect and education consultant for the ALA "has seen an explosion this year in the residential marketplace, first in Christmas lights and televisions and later it will be for desk and task lamps and eventually for replacement bulbs." For consumers who'd rather spend a little less, since LEDs cost between $15-$150 per bulb, the ALA says compact florescent technology is a cheaper alternative and those bulbs are now available in a variety of shapes.
Other than the mercury-free LEDs, CFL's, which were introduced in the 1980s, are touted to reduce air and water pollution. The ALA says they produce three to four times more light than a standard incandescent bulb with the same amount of energy. Incandescent bulbs which are the oldest of the bunch are naturally the most expensive to operate. Reflector lights and halogens are considered part of the incandescent family. The only unfortunate aspect of the CFL is its mercury content, which can make disposing of them a little tedious and time-consuming. However, according to The New York Times, researchers experimenting with particles of selenium found that it bound to nearly all the mercury from a lamp, making it easier to dispose of the nasty substance.
Higher efficiency than incandescent bulbs, halogen bulbs last way longer (up to 2,000-3,000 hours), are conveniently disposable and are able to easily replace most other bulbs in the home. They can't compete with the CFL for energy conservation, though, and are more expensive than the incandescent. But dimming a halogen bulb is easy, which aids in their long life.
These can easily be called the energy suckers of the light bulb world and are being phased out. The cheapest of all at 50¢ to 80¢ a bulb, they are reliable and easily disposed of. But unless dimmed often, they have a very low lifespan and much of their energy is wasted as heat, making them a big no-no with in today's "green" efforts. In the U.S., they are scheduled to be off the shelves by 2012. Rey-Barreau from the ALA says the ban already is taking hold "in Europe where in August of 2009 the government said 'we're done with incandescents' and ceased their immediate sale." He adds that "in the United States it will probably be five to 10 years before we see the extinction of the incandescent bulb, it will not be immediate."
The New York Times has written extensively on the evolution of lightbulbs, covering the subject regularly since the mid-1980s. It's obvious from the articles listed the main reason for developing new sources of light was to make things a lot more energy-efficient.
It's interesting to see how far the issue has come. In 1985 they noted that incandescent bulbs first were being replaced by florescent bulbs. By 1991 they were giving cost comparisons on consumer savings. And then through the '90s and into this century the battle to rid the word of the incandescent bulbs was evident in their reporting.
These are all great tips for consumers who in this still struggling economy are looking to save a buck wherever possible. The Department of Energy reports that Americans spend, on average, five to 10 percent of their electric bills on lighting, which isn't a huge amount, but lowering that number still seems like a bright idea.