Monday, December 8, 2014

Are LEDs the answer to everything?!

Whenever I give a lecture on lighting, I start out with, "Lighting is like a jewelry box.  It can never be too full! And, just like you wear your jewelry in different combinations, you use lighting in different combinations depending upon how you are using a space, or the effect you wish to achieve.
A variety to mix and match.

It's important to make sure that the lamps you use are appropriate to the the task.  For instance, LEDs are directional.  The light will go straight out from the diodes.  So, if you are lighting a cove and want the lights to go up, LED is perfect.  But if you have a cove with a bottom diffuser and want the light to shine up and down, you need to put strips of LEDs back to back - one for the up light and one for the down light.  In this case, you may be better off with tube lighting that glows in all directions.  One type is cold-cathode.  Cold Cathode lasts 80,000-100,000 hours, whereas LED lasts up to 50,000 hours.  

Up lit Cove Lighting Combined with Incandescent Table Lamps

What about the color of LED light?  Yes, they are available in 2700K, the color of incandescent, but often they still look very white.  This is because the CRI (Color Rendering Index) is low.  The highest possible CRI is100, however, most LEDs are about 80.  If color is critical, a quality LED will offer 92-95 CRI.  Fluorescent is typically about 50 - no wonder they make colors look so sickly!

Then there is the temperature at which they operate.  We all know that Halogen is very hot.  Xenon is also quite hot but lasts at least twice as long as Halogen.  Incandescent gives off a bit less heat, and fluorescent is cooler still.  LEDs give off a lot of heat but are built with heat-sinks that absorb and contain the heat, and cold-cathode is amazingly cool.

We have to weigh all the benefits of every type of light, and when mixing different forms of lamps there are many factors to consider - heat and lumen output, Kelvin, CRI, and longevity, not to mention the energy they require.  Whew!  It isn't easy, but at least there are a wide range of choices.  

LED can't be everything to everyone - but it is getting better all the time!