All you need to know about LED Bulbs

Did you know that incandescent lights or the standard light bulbs in your house produce light with only 10% of the energy used, while frittering away 90% as heat?
These outdated bulbs are now increasingly getting replaced by CFLs and LED bulbs. LEDs, in fact, are the latest addition in the lighting industry and are quite amazing once you get to know what they are all about. Let take you through a crash-course on LED lighting and how you can make the right purchase for your home or office.

What is an LED Lamp?

An LED lamp is a light-emitting diode (LED) product that is assembled into a lamp (or light bulb) for use in lighting fixtures.

Characteristics of the LED

Long-life: These lights can last almost five times longer than CFLs and 50 times longer than incandescent bulbs. In terms of running time, you can expect them to last for about 20000-50000 hours!
Maintenance free: Imagine not having to change a light for more than a decade! These lights are practically maintenance free.
Environment friendly: Unlike fluorescent lights, LEDs don’t contain mercury and hence, are safe for your home and the environment.
Minimal heat production: As compared to other lighting sources, LEDs do not build up heat around them. That makes them safer to hold or handle, while preventing unnecessary heating up of your surroundings.
Energy and money savers: The upfront cost of purchasing LED bulbs is higher than that of other light sources, but they are huge energy savers as they don’t fritter away energy on generating heat. In fact, LEDs are known to save 80% power over incandescent bulbs and 40% over CFLs. So you can definitely expect huge savings on your electricity bills.
Durable: Unlike incandescent lights, LEDs do not have filaments which can be damaged. They are solid, sturdy and durable.

Things to Check for While Purchasing LED Bulbs

The wattage of LEDs is different from the wattage of incandescent bulbs and CFLs. So, you can’t simply replace a 60W incandescent light with a 60W LED bulb. The brightness of LED bulbs is indicated by a factor called ‘lumens’, which describes the amount of light in a particular area as perceived by the human eye.
Here’s an indicative list of the lumens in LED lights corresponding to wattage in incandescent lights and CFLs:

Wattage in Incandescent Lights

Wattage in CFLs

Corresponding Lumens in LED Lights

20 W

5 W

200 lumens

40 W

10 W

450 lumens

60 W

15 W

800 lumens

75 W


1100 lumens

100 W


1500 lumens

120 W

30 W

1600 lumens

150 W

40 W

2000+ lumens

Light Distribution:
LED bulbs come in a range of unusual shapes. Unlike standard bulbs, you must check whether the output of light is well distributed or focused in one direction in the LED you shortlist. Your final choice will depend on your intended usage. If you are seeking all-over lighting in a room, the LED you pick up should have at least 120 degrees radius of distribution.

Correlated Colour Temperature:
Unlike incandescent lights, which emit a certain colour, LEDs emanate a variety of colours. What you finally choose will depend on your preferences and requirements. You may refer to the table below to garner an idea of colour temperatures in LEDs.

Colour of Light

Colour Temperature (in Kevins)

Corresponds To

Warm White

2700 K

Regular incandescent light bulb

Neutral White

 3000 K

Regular halogen bulb

Cool White

3500 – 4100 K

800 lumens

Very Cool White

5000 – 6500 K

Colour of daylight

Some LED bulbs are also available in other colours like green, red, blue or amber.

Cap/Fitting: Keep in mind that an LED bulb of similar wattage as your previous incandescent bulb, will not necessarily fit into the same socket. To aid customers in making the right purchase, a cap or fitting size is given with LED bulbs, which indicates the diameter of the bulb’s base.
So make sure you check whether the LED light you are purchasing has the same shape and diameter as the socket or fixture you are intending it for.
Bayonet Caps: This type of bulbs is the push-and-twist kind.

Edison Screw CapsPhilips_led: These bulbs are screwed into the socket.

Here’s an indicator of the base diameters of some Bayonet caps and Edison Screws caps:



Corresponding Diameter

Bayonet Cap



Ba 15d

15 mm

Ba 9s

9 mm

Edison Screw

E 5

5 mm

E 10

10 mm

E 12

12 mm

E 14

14 mm

E 27

27 mm

The most common ones among these are B22, E14, E27 and 2-pins.

Certifications/Quality Check
1) IES Tests: The IES LM-79 test and IES LM-80 tests for LED bulbs were devised by the Illuminating Engineering Society to quantify light output and distribution, performance and lifespan of the bulbs. These tests also identify the colour characteristics of the light emitted.

2) Energy Star Certification: This certification is given out by the Environmental Protection Agency (EPA), basis the results of the IES tests.

1) Bureau of Energy Efficiency
The BEE in India started awarding LED lights rating labels very recently. LED manufacturers can volunteer to apply these labels to their products until December 2016, after which the star rating plan will become mandatory. The labels will indicate efficiency ratings as well as safety requirements.
Here is the proposed star rating plan:

Star Rating

Luminous Efficacy(Lumens per Watt)


≥68 & <79


≥79 & <90


≥90 & <105


≥105 & <120



That about sums up all you need to know to go ahead and purchase LED lights for yourself. We hope you found the information useful!

Article by Piyushi Dhir

You may also like...