Light Power and Lumens: A Guide to Proper Lighting

Light power and luminous flux mean the same thing. Luminous flux is the total amount of light that the led lighting element gives to the environment. So you can think of it as the total brightness produced by the light source. It is the basic unit of measurement of illumination. This value Lumen You will see it in many places with the term. The acronym is Lm is in the form. In this article, you will find answers to many questions such as what is lumen? how to measure it? what is the connection between watts and lumens?

Light Power and Lumens: How to Understand?

The unit of light power is lumen. The higher the lumen value of a led luminaire, the more light it gives. Now let's elaborate a little more on this subject.

What is Lumen? How is it Measured?

Lumen (lm) is a technical unit and refers to the light intensity emitted by the lighting source in all directions. So you need to look at the lumen value to understand how much light power the lighting fixture has. So how is lumen measured? We use an integrating sphere in the laboratory environment to measure lumens. Its other name is integrating sphere. There is a visual below.

We put the lighting products into this sphere. Then we measure the lumen value with the help of this sphere and sensors. As a result, we determine the lm level produced by that lighting fixture. When purchasing a lighting product, it is enough to look at the label, catalogue or datasheet page.

What is the Connection Between Watt and Lumen? What is the Effect on Light Power?

Most of the time you evaluate the power of a light source by watts. This is incorrect. Because watt (w) refers to the electrical power consumed by the light source. Each light source has a lumen level that it can produce per watt. You can see this in the product catalogue or datasheet with the lm/w unit. This unit expresses the efficiency of the product.

What is the Difference between Watts and Lumens?

LED technology is constantly evolving. Therefore, it becomes more efficient over time. In other words, it produces more light with the same energy consumption.

For example:

Let a light source be brand A and be 100 lm/w. Another product is brand B and is 120 lm/w. 120 lm/w means that the brand B device produces 120lm per watt. So you can understand that it is more efficient compared to the other brand A light fitting.

Now let's assume that brands A and B each have 120w/ad. Both brands consume the same electricity. They both consume 120w/h electricity per hour. But while brand A gives 12.000lm light, brand B gives 14.400lm light. You can see the simple calculation below.

• If 1 luminaire of brand A has 120w power and 100lm/w feature: 120w x 100lm/w = 12.000lm light power.
• If 1 luminaire of brand B has 120w power and 120lm/w feature: 120w x 120lm/w = 14.400lm light power.

What if brand A has a higher wattage model? This is where the confusion starts. If we continue with our example, let's assume that there are two models of brand A with 100lm/w as 120w/ad and 200w/ad. As a result, the 120w product gives 12,000lm light, while the 200w model produces 20,000lm light. In other words, of the two sources with the same efficiency, the one with higher wattage of course gives more light.

• A brand 120w model with 100lm/w feature: 120w x 100lm/w = 12,000lm light power.
• A brand 200w model with 100lm/w feature: 200w x 100lm/w = 20,000lm light power.

As in the examples above, you cannot measure the power of light sources with watts. However, you can measure it with Lumen unit. So the Lm value is the only and clearest indicator of light intensity.

Now. LED catalogue page and you can contact us for all your technical questions.