What are Nominal Lumens

What are Nominal Lumens

Nominal lumens are initial lumen output of a light source, such as an LED board or an incandescent bulb, without taking into account any light loss that may occur through a lens or other factors. It represents the brightness of the light source before any light is dispersed or attenuated.

Lumens are a true measure of light output, indicating the total visible light produced by a light source. The higher the lumen rating of a bulb, the more light it provides. However, one need to distinguish lumens from other measurements such as candela or footcandles, which measure light at a single point, whereas lumens measure light output over an area.

Nominal lumens are helpful for understanding the initial brightness or intensity of a light source. It serves as a baseline measurement for comparing different lighting products or calculating the total light output in a given space. It is worth noting that the nominal lumens value does not necessarily represent the actual amount of light that reaches a specific area or surface, as factors like fixture design, light source efficiency, and the presence of optical elements can affect the actual light output.