What is the Difference Between Non-Effective and Effective Lumens?

Have you ever wondered why there are two different lumen values on your lamp’s packaging? In this blog, we will explore the difference between non-effective and effective lumens. What do these two values mean? How can you tell if your lamp optimally distributes light? Let’s unravel this mystery of illumination.

What are Lumens?

Lumens are a measurement of the amount of visible light a lamp produces. In other words, they indicate how bright a lamp is. The higher the number of lumens, the brighter the light.

For example, a 100-lumen lamp emits more light than a 50-lumen lamp. Usually, only one lumen value is provided, but for some lamps, two values appear on the packaging. This is particularly common with so-called DLS lamps.

What is a DLS Lamp?

DLS stands for Direct Light Source. In these lamps, most of the light travels directly from the source to the illuminated object. Examples of DLS lamps include floodlights, GU10 spots, high bays, and LED panels. With a DLS light source, at least 80% of the light reaches the intended illuminated object.

In contrast, traditional bulbs emit light in all directions, whereas DLS lamps focus the light within a specific beam angle (see the diagram below).

Non-Effective Lumens: The Raw Power of Light

One of the values often found on lamp packaging is non-effective lumens, also known as raw lumens. This refers to the total amount of light produced by a lamp directly from the source.

Imagine a floodlight with multiple LED chips. Each chip produces 100 lumens, and the total number of lumens is calculated by adding up all the individual outputs. For example:

24 LEDs × 100 lumens = 2,400 lumens of non-effective light

This represents the raw potential of the lamp—the maximum possible light output it can generate.

Effective Lumens: The Light That Counts

Now comes the crucial part: effective lumens. This value represents the usable light that actually reaches the area you want to illuminate. For example, if you use a floodlight to illuminate a large area, you want as much of that light as possible to be directed effectively at that area. Effective lumens take into account factors such as beam angle and any losses that occur during light dispersion. Depending on how efficiently the light is utilized, the effective lumen value may be lower than the non-effective lumen value. Effective lumens represent the amount of light that falls within the lamp’s beam angle and successfully illuminates the intended surface. Any other light may be lost due to reflections, absorption, or dispersion (e.g., through the glass or reflector in floodlights and high bays), resulting in lumen loss.

Beam Angle: How Light Moves

The beam angle plays a crucial role in determining effective lumens. The way light exits a lamp is influenced by its design and structure, often referred to as the light cone. This determines the angle at which light is emitted.

• A wider beam angle distributes light over a larger area but may reduce effective lumens, as the light is spread out and becomes less concentrated.

• A narrower beam angle focuses the light more intensely, increasing the effective lumen value.

For instance, a 120° beam angle spreads light more widely than a 90° beam angle, covering a larger area. However, with a wider angle (120°), more light is dispersed and lost compared to a narrower angle (90°).

If you install a high bay light in a warehouse at a great height, it is essential to ensure that enough light reaches the floor. The higher the light is mounted, the more lumens are lost. In this case, opting for a smaller beam angle is better, so the light remains more focused. Otherwise, the same number of lumens would be spread over too large an area, reducing brightness at the target location.

Lumens on Packaging

If you see two lumen values on the packaging of a product, you are holding a DLS (Directional Light Source) lamp. For example, let’s say you have just received your floodlight.

• The larger, bold lumen value (marked with the symbol Φ) represents the effective lumens of your floodlight.

• The smaller lumen value (marked with the 360° symbol) represents the non-effective lumens of the floodlight.

The non-effective lumen value (360° symbol) indicates the total raw lumens the floodlight emits initially. The effective lumen value (Φ symbol) shows how much of that light actually reaches the target area within the desired beam angle.

The Power of Light in Two Values

And there you have it—the mystery of the two lumen values on your packaging is solved!

• Non-effective lumens represent the raw potential of the lamp.

• Effective lumens indicate how much of that potential is actually utilized, taking into account factors like beam angle and light loss.

By understanding these two values, you can make more informed decisions when shopping for lighting solutions and ensure you choose the right lamp for your needs.