Why Are LED lights So Energy-Efficient?

LED (or Light Emitting Diode) lights have become quite a sensation due to their energy efficiency and long-lasting characteristics. LED lights are capable of converting 90% of the consumed energy into light.

Don’t be an old-fashioned tube light! Become the trendy LED bulb instead.

Light Emitting Diode or LED is a type of PN junction diode. It is made up of semiconductor material that generates light when current flows through it. It works on the principle of electroluminescence and is used for our day-to-day lighting purposes.

incandescent light bulb, halogen lamp, cfl and led lamp

Different types of bulbs (Photo Credit : Colorcocktail/Shutterstock)

You must have witnessed the rising popularity of LED lights and bulbs. Most of our lighting needs are fulfilled by LEDs today, replacing incandescent bulbs and even CFLs (Compact Fluorescent Lamps). LEDs have been labeled as highly energy-efficient and long-lasting. What is the reason behind it?

Let’s explore more about the science behind these LED lights and make our lives brighter.

How do LED lights work?

LED lights are made up of small light-emitting diodes which are shaped according to our requirements. To understand how a LED light works, we have to get into the details of how a LED works in the first place.

Elements in multi colored icons for mobile concept and web apps

Electronic circuit symbol of LED (Photo Credit : Art studio G/Shutterstock)

A LED is made up of semiconductor material which is in form of a PN junction diode. It emits light in the forward bias (higher voltage is applied to the P-end of the diode than the N-end of the diode) and current flows from P to N. In forward bias, when the holes from the p-type region enter the junction and recombine with the electrons from the n-type region of the LED, energy is released mainly in the form of photons (packets of light). These photons emit light.

Different doping chemicals are added to the LED to emit different colors of light. For example, Aluminium is added to the Gallium Arsenide diode for the emission of visible red light.


Parts of a Light Emitting Diode, i.e. LED  (Photo Credit : Designua/Shutterstock)

Therefore, a LED light works on this principle of electroluminescence to produce light. A point to note here is that a LED runs on Direct Current (DC), but the power supply in domestic households is in form of Alternating Current (AC). Therefore, there is a built-in voltage driver at the base of the LED lights that converts the 120-240 V AC current to 30-60V DC currrent for proper working.

How are LED lights different?

The world has changed and technology has evolved. Thirst for a better living has led to exceptional inventions and discoveries, LEDs being one of them.

headlight meme

LED lights are brighter and better.

LED lighting is quite different from other types of lighting like incandescent and CFL due to a lot of advantages that it has over them.

1) Variety of colors

LEDs are extremely small and can emit a wide range of colors. It’s easy to produce different colors from LEDs and hence they are extensively used in decorations and electronics.

2) Direction

LEDs emit light in only one direction. Hence, it reduces the need for reflectors and diffusers that may result in the loss of light. This feature makes LED an ideal choice for recessed downlights and task lighting.

3) Heat

LEDs emit negligible heat energy as maximum energy is released in form of light. Unlike, incandescent bulbs that emit 90% of their energy as heat and CFLs that emit 80% of their energy as heat.

4) Lifetime

LEDs bulbs last significantly longer than other bulbs because they don’t have any such part that burns like a filament or breaks over time. LEDs can last up to 25,000 hours or almost three years despite constant use.

Why are LED lights so energy-efficient?

LED lights use up to 75% less energy than conventional forms of lights.

LEDs are themselves the source of photons. They generate photons (light particles) when the current is passed through them. They have no filaments or materials that need to be burned to produce light. About 95% of the consumed energy is emitted as light and only 5% is lost as heat. So, LEDs are energy efficient because the wastage of energy is minimum.

Whereas in incandescent bulbs, the filament material has to be heated by the flow of current until it glows which then emits light. In this process, about 90% of consumed energy is lost due to thermal radiation and only 10% is emitted as light.

In CFLs on the other hand, the current is passed through a tube containing argon and mercury vapor and this action generates light energy which however is again only 20% of the consumed energy due to significant loss in form of heat energy.

infographic of incandescent light bulb and energy saving light bulb

LED bulbs are extremely beneficial (Photo Credit : Panacea Doll/Shutterstock)

LED lights deliver more lumens (quantities of visible light) per watt than incandescents. They have higher luminous efficacy. Approximately, 60-watt incandescent bulbs can generate up to 900 lumens, while a LED bulb uses only 6-8 watts.

LED Lights are Worth it!

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LED lights are capable of changing the lighting scenario of the globe completely in the near future. They are also widely used in electronics and gadgets like LED Televisions, watches, mobile screens.


LED lights can help to save a lot of money with regular use and are a better alternative to other lighting options (Photo Credit : twenty20)

Long-lasting, money-saving, and extremely efficient, LED lights are power-packed. They are worth a try and will surely light up your world!

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About the Author

Shreya Chakraborty is pursuing her master’s degree in Physics from NSUT, New Delhi. She is passionate about literature and writing, which allows her to express her scientific interests easily and effectively. She enjoys watching Sci-Fi movies, writing poems and articles, and wondering at the beauty of the night sky.

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