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Conscious of the information of the consumers that we are, the legislator imposes to the manufacturers of the obligatory mentions which must appear on the labels. It's very good but still needs to know what is meant by lumens, kelvin (is it the name of the lamps?) And what about the IRC? Let's decipher all this...

Lumens or the measure of luminous efficiency

The lumen or lm is the unit that measures the amount of light emitted by the bulb. The higher it is, the brighter the bulb is. We used to talk about Watt today, we have to reason in lumen per watt (lm / W)

This brightness varies depending on the type of bulb. Thus an incandescent bulb restores between 15 and 25 lumens per watt consumed while an LED bulb is between 50 and 70 lumens. It lights up so much more for the same power consumption.

Kelvin or the measurement of the color temperature

Let us not forget that white light is composed of different colors each having a wavelength, a different radiation. This color temperature is expressed in kelvin (K)

  • Up to 3300 K light is defined as hot.
  • From 3300 K to 5300 K, it is neutral.
  • Beyond 5300 K, she is Cold.

In summary, the lower the Kelvin degrees, the warmer the light is on the yellow. To illuminate your rooms to live, it is the one that is all right. On the other hand, the higher the Kelvin degrees, the colder the light is on the blue. It will be perfect to light a workshop or garage.

The color rendering index or IRC

This index makes it possible to note the quality of light. The maximum index of 100 is given by daylight and serves as a standard for all other measurements. To be of good quality a lighting must have an index of at least 85%. Halogen bulbs have the best index since it reaches 100%. Compact flucts are between 80 and 90% or more.

The power

She always speaks in watt. Phew, here is one who is familiar to us!

For your safety, it is important to know the maximum power that your luminaire can accept. This indication is on the socket.

The energy label

As in school, the bulbs are rated according to their performance: From A ++ for the most economical to G for goinfres in electricity. This classification is defined according to the lumens restored by Watt consumed (Lumen or lm / W) In principle the class A bulbs have an efficiency higher than 50 lm / W. Those of class G do not exceed 9 lm / W.

Compact fluorescent light bulbs are rated A or B. The LEDs are classified in A although there is still no standard for them. Halogens remain in C or D except economic halogens that go back to B.

Note that from 2016 (unless a postponement in 2018 is authorized by the European Union) it should be marketed only bulbs meeting categories A or B.


She is mentioned in number of hours of use. According to the bulb it varies enormously: From 1000 hours for our old incandescent lamps to 50 000 hours for an LED bulb. But beware, some manufacturers seem very optimistic about the shelf life of their products. Depending on the quality of manufacture, the durations announced are not always at the rendezvous. And some practices can reduce this life span like touching some halogen bulb with the fingers or turning the bulbs on and off.

The number of ignition cycles

Some bulbs, such as compact fluorescents are weakened by repeated ignitions and extinctions. This indication is very important when you choose a bulb to install in a cellar, a corridor, any place where the lights are turned on and off quickly.

The ignition or heating time

This indication corresponds to the time required for the bulb to reach 60% of its brightness. In this area, compact fluorescents are the bad students of the class since they take several seconds before reaching their maximum efficiency.

Again, do not choose this type of bulb for places of passage frequently turned on and quickly extinguished.

Use or not with a dimmer or outside

Depending on how you use the bulb, these indications are valuable. Compact fluorescents, for example, are sensitive to cold and do not like dimmers. While halogens and LEDs, are all terrain.

Sizes and types of sockets

They are expressed in millimeters. Valuable indications when you want to replace a bulb because depending on the luminaire, the height and type of base and socket vary.

Video Instruction: How to Read an LED Bulb Label