Ask a Teacher

Because of their inefficiency, incandescent light bulbs are gradually being replaced in many applications by other types of electric lights such as fluorescent lamps, compact fluorescent lamps (CFL), cold cathode fluorescent lamps (CCFL), high-intensity discharge lamps, and light-emitting diodes (LEDs).  Approximately 90% of the power consumed by an incandescent light bulb is emitted as heat, rather than as visible light. The "Halogen Energy Saver" incandescent is 30 percent more efficient than traditional designs, using a special chamber to reflect formerly wasted heat back to the filament to provide additional lighting power. To improve the efficiency of the lamps, 'coiled coil.' filament is used.  The coiled-coil filament evaporates more slowly than a straight filament of the same surface area and light-emitting power. The halogen cycle increases the lifetime of the bulb and prevents its darkening by re-depositing tungsten from the inside of the bulb back onto the filament.