8 common terms in lighting language explained

How important is the wattage of an LED? What are Lux and Lumens? Which is the best color temperature in Kelvin? The language used in lighting projects can be confusing. We will explain it to you:

Wattage

The watt (symbol: W) is a unit of power. In the case of lighting its an indicator of how much electricity the light will use. BEWARE its not necessarily and indicator of how bright a light is (see "Lumens" and "Efficacy").

Lumens

The amount of light that a bulb or an LED produces. This unit of output is technically known as “Luminous flux.” Knowing how many lumens a bulb produces has becomes increasingly important as consumers make the switch from incandescent bulbs to Energy Saving Led Lights.

Efficacy

Luminous efficacy is a measure of how well a light source produces visible light. It is the ratio of luminous flux to power, measured in lumens per watt. A higher efficacy equals more energy savings over the long term of a project by using less energy to deliver more lumens.

Lux

The Illuminance is a measure of how much luminous flux is spread over a given area. One can think of luminous flux (measured in lumens) as measure of the total "amount" of visible light present, and the illuminance as a measure of the intensity of illumination on a surface.

Kelvin

Scientific unit of temperature. Color temperature is measured on the Kelvin scale. For lighting building interiors, it is often important to take into account the color temperature of illumination. A warmer (i.e., a lower color temperature of 3000-4000K) light is often used in public areas to promote relaxation, while a cooler (higher color temperature of 4000-6000K) light is used to enhance concentration, for example in schools and offices.