Light Emitting Diode (LED) bulbs?

March 29, 2011

What is LED?
LEDs have been around for over 50 years in colours red, orange, yellow, blue, green and then sheer white.

These have come a long way from being tiny indicator lights that tell one when an electronic appliance is switched on. They are beginning to get noticed in India as an energy saving option for lighting buildings and streets though still a speck on the horizon. Delhi has replaced 150 Watt solar vapour lamps in streetlights with 50 Watt LEDs in a residential locality early this year.

What is the benefit?

Unlike incandescent bulbs, LEDs do not have filament that is heated to create light. These are illuminated by the movement of electrons in a semi conductor material (diode). Since electricity is directly turned into light, LEDs waste less energy as heat. Energy consumption is lower than CFLs that use mercury vapour to produce light. LEDs have taken over CFLs promoted as the most advanced lighting device, in energy efficiency. A 5 Watt LED can replace a 15 Watt CFL, saving Rs. 77 on the electricity bill a year.

What is the life span and cost?
LEDs score over incandescent bulbs and CFLs in life span as well. A LED lasts three to five years; an average CFL lasts about 250 days and an incandescent bulb, 41 days. Long life makes it a fit-and-forget fixture, saving cost of maintenance and replacement.

The biggest challenge LED faces is high cost. It is 80 times as expensive as an incandescent bulb and 10 times a CFL. Manufacturers claim high prices are offset by savings but recovering the cost takes 5 to 10 years. A Rs.10, 40 Watt incandescent bulb is replaceable by a CFL that costs Rs. 100. But an LED for the same light output will cost Rs. 800 last year the cost was Rs. 1,200.

Any concern?
These are safer as LED beams do not emit radiation and unlike CFLs, they do not contain mercury.

Any official policy?

At present, there is no subsidy for LEDs. The LED industry pays 28 per cent import duty and 12 per cent VAT. The manufacturers are looking to the government for subsidies to promote LEDs. The technical challenge in popularizing LEDs is to manage the heat generated. If the heat is not dissipated properly the light will begin to dim and the life of the bulb will be reduced. Although LEDs have much higher lighting efficiency than CFLs and incandescent bulbs, the efficiency decreases with use. Unless high standards are maintained in mass production, the output of light and lifespan will be affected.