WHERE DOES LED COME FROM?
LEDs are solid-state devices that convert electrical energy directly into light by a process called electroluminescence.
DO LEDS PRODUCE HEAT?
LED light sources produce dramatically less heat than conventional incandescent lamps, however, the heat output needs to be thermally managed to achieve optimum efficiency. There are many LED lamps on the market with improper or no thermal management of junction heat. Such LED lamps will experience a very dramatic intensity decrease and very short life span.
WHAT IS THE MAIN DIFFERENCE BETWEEN INCANDESCENT AND LED LIGHT SOURCES?
Traditional incandescent lights contain a filament that’s heated until it emits light. This process is called incandescence. The hotter the filament, the more light the lamp produces. Efficiency of an incandescent lamp is less than 5%, which means 95% of the energy is wasted in the form of heat. Filament in an incandescent light is fragile and burns out or breaks relatively easy. Its life span is generally less than 3000 hours.
WHAT IS THE MAIN DIFFERENCE BETWEEN A FLUORESCENT AND LED LIGHT SOURCE?
Fluorescent lamps generate light by a high voltage arc passing through mercury vapor. The arc generates high energy ultraviolet light that is absorbed by a phosphor coating inside the lamp, causing it to glow, or fluoresce. Every fluorescent lamp contains highly poisonous mercury, so if the lamp breaks, the surrounding environment will be exposed to it. Linear fluorescents have life spans of approximately 10,000 to 20,000 hours. Compact fluorescent (CFL) life span varies from 1,200 to 20,000 hours.
I HEARD THAT LED LIFE IS OVER 100,000 HOUR. IS IT TRUE?
No, it is not. LEDs may go over 100,000 hours but only in perfect laboratory conditions. Real life environments are substantially different. Before we answer the lifespan question, let’s first define what lifespan of an LED really means. In traditional incandescent lamps, lifespan is defined as a time to the point where 50% of all sampled lamps will go defective. LED is very different. If designed properly, LEDs will work for decades without catastrophic failure. However, the light output will slowly decrease. New industry standards define LED lifespan as a time where luminous intensity reaches 70% of its initial value.
The lifespan of the LED depends on thermal management of the LED lamp and/or system. With proper thermal management, smaller lamps like the GU10 will easily reach 30,000 hour mark. Compared to the 2,000 hour lifespan of incandescent lamps or 10,000 hours of compact fluorescents, LEDs are the very clear winners.
AREN’T ALL LEDS THE SAME?
No. LEDs, LED lamps, and LED lighting systems are quite different in design and quality. A good LED lamp or system design is much more efficient than incandescent or compact fluorescent lighting. Unfortunately, most LED lighting available for consumers today is of marginal quality and expensive. Poorly designed luminaries can be relatively inefficient, fail, or deliver poor light characteristics.
ARE LED LAMPS DIMMABLE?
Properly designed LED lamps and/or systems are fully dimmable. However, there are many LED lamps on the market without dimming capabilities that may lead to shortened lifespans. It is important to mention that dimming characteristics of LED lamps are different compared to incandescent. Usually the slope of LED dimming is much steeper.
DOES TURNING AN LED LAMP ON AND OFF SHORTEN ITS LIFESPAN?
No. Unlike fluorescent light sources (compact or linear), LED light sources are “switch” friendly. Turning them on and off extends their lifespan. A fluorescent lamp’s lifespan will be dramatically shortened if turned on and off.
I DO NOT LIKE THE QUALITY OF LIGHT GENERATED BY FLUORESCENT LIGHT SOURCES. ARE LED’S DIFFERENT?
Definitely. LED light sources generate much more pleasant and vibrant light. However, color-rendering properties are not as good as incandescent, especially in the red spectrum.
HOW EFFICIENT ARE WHITE LEDS?
LED light sources are extremely efficient. Today’s best commercially available LED sources can generate close to 90 lumens per watt. Incandescent lamps are typically 10 to 12 lumens per watt, halogen lamps 20 to 25, and fluorescent lamps 40 to 60.
WILL LED LIGHTING BECOME MORE EFFICIENT OVER TIME?
Yes. Even today we are experimenting with LEDs that are generating close to 150 lumens per watt. We can expect to see such LED light sources on the market within the next 5 years.
- No abrupt burnout like incandescent bulbs
- On/off cycling doesn’t diminish lifespan as with CFLs
- Instant on; no warm up time needed as in HID lamps
- Produce greater light per watt than incandescent bulbs
- Easily dimmer
- Have a useable life 30 to 50 times longer than incandescent bulbs and 3 to 5 times longer than CFLs
- Do not contain dangerous mercury, unlike CFLs
- Very small size gives them more design options
- Solid-state components make them shock resistant and virtually unbreakable
- Deliver efficient directional light, unlike incandescent bulbs and CFLs