Common LED Lighting Myths & Facts

Common LED Lighting Myths

There’s never a shortage of myths about new technologies. Even nearly a decade after the introduction of the LED light bulb, there are still misunderstandings about them which, for the most part, are based on faulty knowledge and the resistance to adapt to something new.

LED Lighting Technology Facts

Why are LED lights better than incandescent light bulbs?

As many people already know, incandescent light bulbs make light by heating up a coiled tungsten wire filament in a vacuum inside a sealed glass bulb. The amount of power required to make the filament glow at its optimal level (for lifespan and brightness) was rated in watts. Because about 90% of the wattage used goes to heating up the filament, incandescent bulbs are pretty inefficient at making light —but you can use one to bake a cake. Ultimately, the bulb’s filament breaks due to heat —after about 1,000 to 2,000 hours on average.

Light emitting diodes (LEDs) are semiconductors in a transparent epoxy casing. LEDs emit light through electroluminescence — that is, electrical current energizes electrons in the semiconductor material until the electrons emit a photon. Most of the electricity entering an LED is used to make light. It takes just 1.6 volts of DC current to light a single LED.

LEDS can also be built to emit specific colored light by using specific kinds of semiconductor materials to control the wavelength of the light it emits. For example, aluminum indium gallium phosphide (AlInGaP) is used as the semiconductor material for LEDs designed to emit light in wavelengths of 565 to 645 nanometers —or lime-green to red. White LED bulbs, however, rely on mix of colors and phosphor coatings to emit white light. This initially resulted in different manufacturers’ white light bulbs not looking exactly white. It wasn’t until 2008 that an international manufacturer standard codified light output (in lumens) and color temperature (in degrees Kelvin or K°).

Those standards are also being applied to incandescent light bulbs. For example, a standard indoor 60 watt lightbulb has a color temperature of 3,000°K and kicks out 800 lumens.

LED Myths

LEDs last forever.

Because LED bulbs don’t heat up filaments, there’s very little thermal stress —which gives them an extended lifespan. That said, it’s not true that they last forever. LED bulbs work by using what’s called a “driver” circuit. Basically, this is a small circuit board mounted below the LEDs on the bulb. It’s composed of a couple of diodes and a few other semiconductors that change the household 120 AC current into DC voltage. While the LED’s themselves don’t get hot, the semiconductors on this circuit board can get a little warm. On cheaply made or defective LED bulbs, this board can actually get quite hot. When that happens, it’s a sure sign the board will burn out soon. However, for most bulbs with properly working boards, the actual LEDs will last thousands of hours and eventually dim.

LED bulbs are so expensive.

LEDs used to be expensive ten years ago. LED prices have fallen by about 1/5, especially as more companies are competing against each other. A six pack of soft white “60 watt equivalent” non-dimmable LED bulbs that only use 9 watts sells for under $15 and each is rated for a 15,000 hour lifespan.

Sure, incandescents bulbs are still dirt cheap — less than 40¢ for a 60 watt bulb with a 2,500 lifespan. But the real expense comes from using the incandescents. A 60 watt bulb will use 150,000 watts during its lifespan – that’s 150 kWh! At 10¢/kWH that adds up to $15 —practically the cost of six pack of LED bulbs! For the same 2,500 hours, a 9 watt LED bulb will use just 22500 watts or 22.5 kWh —$2.25! For my money, that 40¢ incandescent sounds too expensive! In the long term LED bulbs last longer and will save you more money than incandescent bulbs.

All LED light bulbs shine with a very white light.

Remember that LED bulbs can be tuned to have different color temperatures. The trick is knowing what the best temperatures are for what you want the light for and/or where you have the light. Basically, there are three magic number ranges to remember:

  • 2,700 to 3,000 degrees Kelvin (K) —warm white or soft white. This is the same color temperature of tungsten incandescent bulbs.
  • 3,500 to 41,000 degrees Kelvin — Cool white.
  • 50,000 to 65,000 degrees Kelvin — Daylight. Tends to be bluish in comparison to the others. Think sunny, blue-sky day.

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