When Thomas Alva Edison gifted the world with the very first electric lamp, he might not have paid much attention to the efficiency or the efficacy of it. The invention of the first electric lamp was after all, a successful endeavor and a huge leap forward for science. Further, the environmental conditions then were far better than they are now for them to care much about such trivial issues!
However, things are now much different. In these times of global warming and energy scarcity, incandescent lamps are proving to be way more costly both in terms of environmental impact and energy efficiency. Many developed nations are also planning to phase out incandescent lamps, because suitable energy-efficient alternatives are now available.
Currently, there are two types of energy-efficient lighting technologies available in the market – CFLs (compact fluorescent lamps) and LEDs (light emitting diodes). A light-emitting diode (LED) bulb is a semiconductor light source. LED lamps are several times better than other light sources like fluorescent lamps or incandescent lamps due to their longer lifespan and higher energy efficiency. Further, LED lamps come into maximum brightness without any warm up time, unlike fluorescent ones. It is now preferred by users across diverse fields such as domestic, industrial, commercial and advertising.
LED lamps have been around for quite some time now, but they were only used in gadgets like remote control, decorative lights, digital clocks etc., LED bulbs differ from traditional incandescent bulbs in the way they produce the light. While old fashioned incandescent bulbs emit light when electricity is passed through a metal filament, LEDs produce light by using a semi-conductor that illuminates when electrical current passes through it.
Since LED lamps have been recently employed for household lighting, they are costlier than other types of energy efficient lamps (like CFLs) and are also only available in focused brightness. However, with increasing popularity and advancements in technology, these difficulties are being overcome.
LEDs are more expensive, but they do have benefits over the other lamps like CFLs:
- LEDs use 90% less energy than incandescent lamps (CFLs use 60-80% less than incandescents, and halogens use 20-30% less)
- LEDs are expected to last around 25-30 years, dependent on usage
- LEDs emit light instantly at start-up unlike CFLs which flicker and take time to light up
- LED lights don’t contain mercury or other toxic chemicals (CFLs do, though it’s only a minute amount)
- LED lights, like halogens, work fine in low temperatures, whereas CFLs don’t
- Although a standard incandescent lamp emits much brighter light at about 840 lumens, LEDs are evolving fast to perform on par (the Philips L Prize emits 940 lumens)
The comparison chart for different types of light sources based on energy efficiency and lifespan:
|Power used (watts)||60||43||14||10|
|Color rendering index||100||100||82||82|
|Bulb lifetime (years)*||0.5||0.5||4.6||>11.4|
Source: Wikipedia | *Comparison based on 6 hours use per day
Although they are still expensive to produce, LEDs are becoming cheaper, as predicted by the Haitz’s Law. Aided by technical advances and economies of scale, LED lamps are also getting brighter, which means manufacturers can use fewer LEDs per bulb, further driving down costs. Roland Haitz believes that sometime around 2020, bulbs built for the conventional infrastructure will max out, since at some point additional brightness from a single socket would be overkill.