What are Lumens and why do we use them to measure LED lights?

To choose the correct LED lighting for your needs, it is important to understand what lumens refer too. Lumens measure the brightness of a light source. Here we will take a closer look at why light is measured in this way, and what this means for you.

What are Lumens?

Lumens, often written as ‘lm’, is the unit of luminous flux. They measure the amount of light output visible to the human eye from a source. The higher the lumen value, the more output there is, and thus the brighter the luminaire will appear.

Why is light from LEDs measured in lumens?

Before LED lighting became commonplace, measuring light could be considered relatively straightforward. With non-LED bulbs, standard options were 25, 24, 60, and 100 Watts. In older traditional incandescent light bulbs, light was measured in watts. Watts measure the amount of energy within a light and conveys how much power the bulbs used. Typically, more wattage meant a bright light, so people started to associate Watts with the level of brightness of a light. Now, with more efficient LED lighting options are available, this assumption no longer works.

LEDs do not conform to the same standards as traditional bulbs. Therefore, with the evolution of LED lighting and its increased implementation, the term lumen has also become more commonplace to convey brightness. Now that the lighting industry has improved to utilise more energy-efficient lighting options, wattage as a measurement no longer always means a brighter light (unless you are remaining within the same type of light bulb). To avoid these inconsistencies across technologies, lumens has become the preferred measurement for LED lighting.

For example, A 20Watt LED bulb is more efficient, and therefore appears much brighter than say a 40Watt incandescent bulb. As the LED bulb produces 1600 lumens, whereas the incandescent one, only produces 450 lumens.

How useful are Lumens?

Lumens are a useful measurement to consider if trying to determine how many light fittings to buy for a particular space. Many facilities have minimum requirements for visibility purposes. If a certain number of lumens is required per square meter, by knowing the lumen value of a light fitting, you can calculate and install the correct number of lights.

Based on the consistency of using Lumens to measure light, this unit of measure gives a uniform approach to light output and brightness that works across all varying lighting technologies. Therefore, it is most certainly a useful unit of measure to look out for in LED lighting!