Energy-efficient bulbs also offer environmental advantages. Energy efficiency in light bulbs depends upon several factors, including light generation, usable energy and heat generation.
Different types of light bulbs use electricity in different ways to generate light. These styles include the incandescent bulb, the compact fluorescent bulb (CFL) and the light-emitting diode (LED) light. The incandescent bulb includes standard bulbs, long-life bulbs and halogen bulbs.
CFLs differ in the warmth of the light they emit, expressed as its Kelvin (K) number, found on the packaging of Energy Star bulbs. The bulbs differ in how light is generated, which in turn affects their efficiency.
Light Generation
The question of energy efficiency boils down to how each of these bulbs generates light. The incandescent bulb contains a filament which is heated by electricity. The compact fluorescent bulb produces ultraviolet light by passing electricity through a tube containing mercury vapor.
Finally, the LED produces light through the use of light-emitting diodes. A diode is a semiconductor through which energy flows in one direction. These differences are key to how energy is used.
Usable Energy
Energy efficiency boils down into which of the bulbs uses more energy for light. The incandescent bulb is the least energy-efficient. Energy Star reports that 90 percent of its energy is given off as heat rather than light, thereby wasting most of the energy needed to provide light.
CFLs, on the other hand, use about 25 percent of the energy an incandescent bulb requires while producing 90 percent less heat, according to the U.S. Department of Energy. More energy is converted into light rather than heat, making it more energy-efficient. The LED is 80 percent energy-efficient, explains the LC LED Corporation, releasing little heat.
Longevity
For a complete assessment of energy efficiency, it's necessary to look into other factors, including the bulb's longevity. The design of each bulb style affects its efficiency and economic cost. Energy Star estimates that a long-life 60-watt incandescent bulb will last about 2,000 hours.
However, a compact fluorescent bulb can last up to 12,000 hours. The LED surpasses both these bulbs, however, by lasting up to 100,000 hours, estimates the LC LED Corporation. The lifespan of the bulb means that you will benefit by its energy efficiency longer.
Energy Efficiency
The energy efficiency of different light bulbs include savings for you as well as benefits for the environment. According to the U.S. Department of Energy, you will save over $100 over the lifetime of a CFL versus an incandescent bulb.
Both CFLs and LED lights use less energy to provide the same amount of light as an incandescent bulb. Energy Star estimates that if all American households replaced just one incandescent bulb with an energy efficient one, the energy savings would translate into a reduction of 9 billion pounds of greenhouse gas emissions per year.
Sources:
Energy Star: Learn About LEDs – www.energystar.gov
LC LED Corporation: Advantages of LED Lights – www.lc-led.com
U.S. Department of Energy: Frequently Asked Questions – Electricity – www.eia.doe.gov
