In what ways does warm white LED street light show low energy efficiency?

Warm white LED street lights are generally considered energy-efficient compared to traditional lighting technologies. However, there are some specific ways in which they might show relatively lower energy efficiency compared to cool white LED street lights. These include:

Luminous Efficacy
Luminous Efficacy: Warm white LEDs often have slightly lower luminous efficacy (lumens per watt) than cool white LEDs. This means they produce fewer lumens per unit of energy consumed. The phosphors used to create the warm white light can be less efficient at converting electrical energy into light.
Higher Energy Consumption for Equivalent Brightness
Higher Energy Consumption: To achieve the same level of brightness (measured in lumens), warm white LEDs may require slightly more power than cool white LEDs. This can result in marginally higher energy consumption over time.
Color Rendering

Color Rendering Index (CRI): Warm white LEDs often have a higher CRI, which means they render colors more accurately and naturally. However, achieving a high CRI can sometimes require more energy, making them slightly less efficient in terms of lumens per watt compared to lower-CRI cool white LEDs.
Heat Management
Heat Dissipation: Warm white LEDs might generate more heat due to the inefficiency in the phosphor conversion process. This can necessitate better heat management systems, which can indirectly impact overall energy efficiency and longevity of the LEDs.
Specific Use Case Efficiency
Application-Specific Efficiency: In some applications, the perceived brightness of cool white light might be higher than warm white light, leading to the need for higher lumen output from warm white LEDs to achieve the same visual effect, thus using more energy.
Mitigating Factors
Overall Efficiency Gains: Despite these relative inefficiencies, warm white LEDs still represent a significant improvement over traditional incandescent and fluorescent lighting in terms of energy savings.
Technological Advances: Ongoing advancements in LED technology continue to improve the efficiency of warm white LEDs, narrowing the gap between warm and cool white LED efficiencies.

While warm white LED street lights may exhibit slightly lower energy efficiency compared to cool white LEDs due to factors like luminous efficacy and heat management, they still offer substantial energy savings over traditional lighting options. The choice between warm white and cool white LEDs often involves balancing energy efficiency with factors like visual comfort, aesthetic appeal, and environmental impact.