LED lighting yields outstanding energy efficiency and lower energy costs to improve health, economic vitality and security

 

Luminous Efficacy Energy efficiency of light sources is typically measured in lumens per watt (lm/W), meaning the amount of light produced for each watt of electricity consumed by the light source. This is known as luminous efficacy. The U.S. Department of Energy's long-term research and development goal calls for white-light LEDs producing 160 lm/W in cost-effective, market-ready systems by 2025.

Currently, the most efficacious white LEDs can perform similarly to fluorescent lamps. However, there are several important caveats: Color QualityThe most efficacious LEDs have very high correlated color temperatures (CCTs), often above 5000K, producing a “cold” bluish light. However, warm white LEDs (2600K to 3500K) have improved significantly, now approaching the efficacy of CFLs. In addition to warmer appearance, LED color rendering is also improving; warm white LEDs are now available with color rendering index (CRI) of 80, equivalent to CFLs. Driver Losses Fluorescent and high-intensity discharge (HID) light sources cannot function without a ballast, which provides a starting voltage and limits electrical current to the lamp. LEDs also require supplementary electronics, usually called drivers. The driver converts line power to the appropriate voltage (typically between 2 and 4 volts DC for high-brightness LEDs) and current (generally 200-1000 milliamps or mA), and may also include dimming and/or color correction controls.