Get the facts on LED light­ing

DEMM Engineering & Manufacturing - - MAINTENANCE MATTERS - Fea­ture sup­plied by Vince Seimer of

While LED, or light emit­ting diode, tech­nol­ogy has been around for 90 years, only within the last decade has the tech­nol­ogy be­come cost ef­fec­tive and able to pro­duce the brighter and whiter light nec­es­sary for the home mar­ket.

Still, it is an in­vest­ment that pays off over time, with its higher ini­tial cost com­pared to in­can­des­cent bulbs be­ing off­set by sig­nif­i­cant op­er­at­ing cost sav­ings and a longer life span.

Change has been dra­matic in the last year, with LED mov­ing from an al­ter­na­tive in light­ing to mak­ing in­can­des­cent light­ing ob­so­lete. The speed with which this has oc­curred has left many con­sumers un­aware of the dif­fer­ences and con­fused by the seem­ingly end­less op­tions that LEDs pro­vide. If you find your­self in a po­si­tion to ad­vise end users, then here are a few in­sights to help you.

First, bulbs are no longer bulbs in the tra­di­tional sense. LED lights typ­i­cally con­tain one watt light emit­ting diodes chips com­bined on a re­flec­tive sur­face.

A seven watt LED bulb/light will have seven diodes and a 12 watt will have a dozen. In con­trast to con­ven­tional light bulbs, the diode chips have life­spans longer than most house­hold ap­pli­ances. They are typ­i­cally rated to last 20,000 to 100,000 hours.

The most common threat to a long life is ex­ces­sive heat build up, as the diodes are more sen­si­tive to heat.

When shop­ping for bulbs, most con­sumers are prob­a­bly ac­cus­tomed to look­ing for watts as an in­di­ca­tion of how bright the bulb will be.

This as­sump­tion does not ap­ply for LEDs. Wattage is a mea­sure of power us­age. While we have grown ac­cus­tomed to this power us­age di­rectly cor­re­lat­ing to the bright­ness of the bulbs peo­ple buy, the ef­fi­ciency of LEDs in cre­at­ing light can vary sig­nif­i­cantly. The new mea­sure of com­par­i­son is ‘lu­mens’.

All LED bulbs use far less power than con­ven­tional bulbs, but the com­pa­ra­ble bright­ness of an LED bulb to a 60-watt in­can­des­cent can vary from seven to 12 watts. Hence, lu­mens is a bet­ter guide. In terms most con­sumers are used to, a 40 watt in­can­des­cent bulb pro­duces 400 lu­mens, a 60 watt bulb pro­duces 800 lu­mens, a 75 watt pro­duces 1,100 lu­mens and a 100 watt pro­duces 1,600 lu­mens.

One in­de­ter­mi­nate in com­par­i­son of in­can­des­cent with LED might in­clude the ef­fi­ciency by which the light fix­ture re­flects light into the room.

LEDs of­fer a wide ar­ray of choices in the light colour they pro­duce. For home light­ing, the op­tions com­monly range from ‘warm white’ to ‘cool white’ and are mea­sured on the Kelvin scale.

The in­can­des­cent light­ing to which we are ac­cus­tomed to is at the lower end of the Kelvin scale, in the 2,700 to 3,500K range. The lower the num­ber, the warmer (yel­lower) the light is. In con­trast, the cooler (bluer) light, sim­i­lar to the f lu­o­res­cent light­ing common in com­mer­cial of­fices, falls in the up­per range, be­tween 6000 and 6,500K.

At NZ LED we un­der­stand that many con­sumers se­lect the light colour de­pend­ing upon per­sonal pref­er­ence or the ap­pli­ca­tion, with cooler lights common in work ar­eas of the home such as garages and kitchens where a more vis­i­ble light­ing is ad­van­ta­geous, and the more com­fort­able, warmer lights se­lected for lounges and bed­rooms.

LEDs have another dif­fer­ence with in­can­des­cent and that is when it comes to dim­ming. Be­cause of their cir­cuitry, LEDs are com­monly not com­pat­i­ble with dim­ming switches. Pay­ing more for a com­pat­i­ble LED driver, and some­times also chang­ing the dim­ming switches, is re­quired.

With­out the ap­pro­pri­ate cir­cuitry, your LED bulb or light will f licker or not work at all. Sim­ply en­sure the LED you buy is en­gi­neered to be dimmed if that is your re­quire­ment.

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