How is efficiency in lighting measured?

Efficiency in lighting is primarily measured by lumen output, which quantifies the amount of visible light emitted by a light source. This measurement is critical because it directly relates to the effectiveness of a lighting system in providing adequate illumination for a given space. When we discuss lighting efficiency, we are often interested in how much light is produced per unit of power consumed, typically expressed in lumens per watt (lm/W). This metric highlights how well a light source converts electrical energy into visible light, allowing comparisons between different lighting technologies, such as incandescent, fluorescent, and LED bulbs.

While wattage refers to the amount of electrical power consumed by a light source, it does not provide a complete picture of how effective that power is in generating light. Similarly, illuminance measures the intensity of light arriving at a surface and is influenced by distance and the angle of the light, rather than the efficiency of the light source itself. Voltage, meanwhile, relates to the electrical potential involved but does not directly inform us about light output or efficiency. Therefore, lumen output is the most appropriate measure of efficiency in lighting.