LED Light Bulb Primer

LED light bulbs

LED (light emitting diodes) light bulbs are one of the great new energy conservation inventions that has potential to make a significant impact on CO2 levels world wide.  Led bulbs emit a much higher percentage of light in the desired direction and also generate very little unwanted heat. The energy savings may be doubled in air-conditioned environments where each watt of incandescent lighting can add another watt or more to the power needed for air conditioning.

Led bulbs can operate for 30,000 hours or more. One LED light bulb can easily outlast 30 incandescent bulbs or 6 compact fluorescents light bulbs. Led bulbs cost less than the bulbs they replace over their lifetime. When operating 12 hours per day, LED light bulbs can last 7 years or more. Unlike incandescent light bulbs, they are not sensitive to shock, vibration, or the extreme temperature changes that can quickly ruin them. And unlike fluorescent bulbs which wear out faster if they are frequently turned on and off, led bulbs are not affected by frequent on-off switching.

In fact, the United States, environmental protection agency encourages the use of LED light bulbs.

The high cost of producing LEDs has been a roadblock to widespread use but the price has been gradually falling due to demand which portends upcoming competitive pricing with CFLs and incandescents. LEDs may soon become the standard for most lighting needs.

How does an LED light bulb work?

LED lights work very similarly to standard light bulbs except they are smaller and contain no filament. Instead of a filament, an LED creates light using nothing but the movement of electricity along the path of its semiconductor. As the electrons stream across the semiconductor, they create electromagnetic radiation. Some forms of this electromagnetic radiation can take the form of visible light, which humans can perceive via sight.

LED Lighting

LEDs are solid light bulbs which are extremely energy-efficient. Until recently, LEDs were limited to single-bulb use in applications such as instrument panels, electronics, pen lights and, more recently, strings of indoor and outdoor Christmas lights.

LED Clustering

Manufacturers have expanded the application of LEDs by “clustering” the small bulbs. The first clustered bulbs bulbs were used for battery powered items such as flashlights and headlamps. Today, LED bulbs are made using as many as 180 bulbs per cluster, and encased in diffuser lenses which spread the light in wider beams. Now available with standard bases which fit common household light fixtures, LEDs are the next generation in home lighting.

Benefits of LED light bulbs

  • Long-lasting – LED bulbs last up to 10 times as long as compact fluorescents, and far longer than typical incandescents
  • Durable – since LEDs do not have a filament, they are not damaged under circumstances when a regular incandescent bulb would be broken. Because they are solid, LED bulbs hold up well to jarring and bumping
  • Cool – these bulbs do not cause heat build-up; LEDs produce 3.4 btu’s/hour, compared to 85 for incandescent bulbs. This also cuts down on air conditioning costs in the home
  • Mercury-free – no mercury is used in the manufacturing of LEDs
  • More efficient – LED light bulbs use only 2-10 watts of electricity (1/3rd to 1/30th of Incandescent or CFL) Small LED flashlight bulbs will extend battery life 10 to 15 times longer than with incandescent bulbs. Also, because these bulbs last for years, energy is saved in maintenance and replacement costs. For example, many cities in the US are replacing their incandescent traffic lights with LED arrays because the electricity costs can be reduced by 80% or more
  • Cost-effective – although LEDs are expensive, the cost is recouped over time and in battery savings. For the AC bulbs and large cluster arrays, the best value comes from commercial use where maintenance and replacement costs are expensive
  • Light for remote areas – because of the low power requirement for LEDs, using solar panels becomes more practical and less expensive than running an electric line or using a generator for lighting
Choosing an LED lightbulb

Many different models and styles of LED bulbs are emerging in today’s marketplace. When choosing a bulb, keep in mind the following:

  • Estimate desired wattage – read the package to choose desired illumination level. For example, a 3W LED is equivalent in output to a 45 W incandescent
  • Choose between warm and cool light – new LED bulbs are available in ‘cool’ white light, which is ideal for task lighting, and ‘warm’ light commonly used for accent or small area lighting
  • Standard base or pin base – LEDs are available in several types of ‘pin’ sockets or the standard “screw’ (Edison) bases for recessed or track lighting
  • Choose between standard and dimmable bulbs – some LED bulbs, such as the LumiSelect series, are now available as dimmable bulbs

The common styles of LED bulbs include the following:

Diffused bulbs

In this style LED bulb, clusters of LEDs are covered by a dimpled lens which spreads the light out over a wider area. Available in standard Edison bases, these bulbs have many uses, such as area lighting for rooms, porches, reading lamps, accent lamps, hallways and low-light applications where lights remain on for extended periods. more info

EvoLux LED bulb

Diffused high power bulbs

Designed for standard household use, these bulbs produce light equivalent to a 100-watt incandescent bulb. The EvoLux (pictured), and ZetaLux (pictured above) are the first UL Listed and FCC approved LED light bulbs for general household illumination. more info

LED track light bulb

Available in pin base or standard (Edison) base, LEDs are ideal for track lighting. LEDs do not contribute to heat buildup in a room because no matter how long they remain on, they do not get hot to the touch. Also, because they are 90% more efficient than incandescents, and last 10 times longer than CFLs, the frequency of changing bulbs is greatly reduced.

LED recessed bulb and module

LEDs are now available for standard recessed lighting pots and housings. The light output and color quality are similar to incandescent downlights, but draws only about one-fifth of the power. Also, because they are 90% more efficient than incandescents. and last 10 times longer than CFLs, the frequency of changing bulbs is greatly reduced. more info

LED spotlight

Spotlight and Floodlight LEDs

The spotlight LED lacks a dispersing lens, so it appears brighter as its light is directed forward. It runs cool and will last over 50,000 hours due to advanced thermal management design. The floodlight model gives a spread-out dispersed light. Well suited for ceiling lights, outdoor floodlights. retail display lighting, landscape lighting and motion sensors. more info

LED Terminology
  • CRI - Coloring Rendering Index. CRI represents the quality of light and its faithfulness to render colors correctly. The EvoLux bulb, for example, features a CRI of 75 for Cool White and 80 for Warm White making it one of the highest in the industry.
  • CCT – Correlated Color Temperature is the measure used to describe the relative color appearance of a white light source. CCT indicates whether a light source appears more yellow/gold/orange or more blue, in terms of the range of available shades of “white.” CCT is given in kelvins (unit of absolute temperature).
  • RGB – stands for red, green, and blue, the three primary colors of light. When the primaries are mixed, the resulting light appears white to the human eye. Mixing the light from red, green, and blue LEDs is one way to produce white light. The other approach is known as phosphor conversion5
  • Luminous Flux – the flow of light measured in lumens. With light bulbs, it provides an estimate of the apparent amount of light the bulb will produce.
LED Colors
  • Red – red is the traditional color for maintaining night vision.
  • Green - green is now the preferred color for pilots and the military. The green color is also great for retaining night vision, and it doesn’t erase the red markings on maps and charts.
  • Blue – many people like the blue because it is very easy on the eyes. Blue appears to be a good reading light for elderly eyes. Elderly folks report that they can read under the blue light for hours without eyestrain, compared to severe eyestrain in less than 30 minutes with incandescent lighting.
  • White – the most popular of the LED colors. It produces a soft white light, without harsh reflection, glare or shadows.
  • Amber – LED amber bulbs do not attract flying insects, as do ordinary white bulbs. Amber LEDs are used outdoors in areas such as patios and decks where insects flying around lights are a nuisance.

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