Is the Higher the Power of LED Luminaires, the Brighter They Are?

Created on 04.27

In daily life, most people think that the higher the power of LED luminaires is, the brighter they will be. In most cases, it seems so on the surface, but if we look deeper? The answer is no. To judge whether a luminaire is bright enough, it is not the power that matters, but the luminous flux.

Power refers to the work done by an object per unit time, with the unit of watt (W). The higher - power luminaires consume more energy and use more electricity. However, this is not the key factor affecting the brightness of luminaires and can only be used as a reference factor.

Luminous flux refers to the amount of light that can be perceived by the human eye in a unit area, with the unit of lumen (lm). The larger the lumen value, the higher the brightness, which is the most critical factor directly determining the brightness of luminaires.

The brightness of luminaires can be calculated, but another necessary parameter must be known: luminous efficacy, with the unit of lumen per watt (lm/W). For different light sources with the same luminous flux, the less energy consumed, the higher the luminous efficacy. Luminous flux = luminous efficacy * power.

Let's look at an example: Calculate the luminous flux emitted by a luminaire per unit time when we know its power.

For a 36 - W lamp with a luminous efficacy of 80 lm/W, the luminous flux is 2,880 lm.

For a 30 - W lamp with a luminous efficacy of 110 lm/W, the luminous flux is 3,300 lm.

From the above example, we can clearly see that the luminous flux of the 30 - W luminaire is larger than that of the 36 - W luminaire. Therefore, the 30 - W luminaire will be brighter than the 36 - W one. The luminous flux determines their brightness.