The first light bulbs — and the ones that are used in most homes — are incandescents. Basically, these bulbs follow Thomas Edison’s original design: an electrical current runs through a filament in a glass bulb. The filament then heats up, emitting light, as well as a lot of heat.
In terms of base price, incandescent bulbs seem like the cheapest option: a four-pack costs somewhere between$2 and $3. But the cost goes up once you screw them into a lamp: incandescents use between 20 and 100 watts per hour, which translates into 2-12 kilowatts per month. Also, they don’t last too long: most bulbs work for between 750 and 1,000 hours, or 6-8 months, which means that they need to be replaced fairly often.
They are also the most convenient lighting option. Incandescent bulbs can be used with dimmer switches and are available in a wide variety of shapes and sizes, making them a perfect fit for almost any lighting design. They are easy to dispose of and, after more than 100 years of use, most of the bugs have been worked out.
The current lightbulb leaders are compact fluorescent lamps or CFLs. First developed in the early 1980’s, CFLs didn’t become really popular until the last few years. Part of the reason for this is cost: although their price has dropped in recent years, CFLs still run $2 and up per bulb, about four times as much as incandescent bulbs. On the other hand, CFLs also last a lot longer: most will run for between 6,000 and 10,000 hours, or 4-7 years of normal use. In fact, given that they will run for 6-10 times longer than incandescents, their basic price is up to 50% less than incandescent bulbs. And CFLs also use a lot less electricity: a 26-watt compact fluorescent puts out as much light as a 100-watt incandescent, but only uses about a quarter of the electricity. See post here. See earlier post on Lighting the Way With LED here.