A wide range of color temperature options are available in LED lighting designs using the Citizen LED Array chip. These are:
2700 degree K
3000 degree K
3500 degree K
4000 degree K
5000 degree K
It is important to know what these color temperatures represent, how they interact with human perceptions and moods, which locations are best served by each, and the energy efficiency of the fixture vs color temperature.
The color temperature scale was developed to help describe the overall hue of the artificial light source and to attempt to relate it to natural light sources. 2700 degree K light has a yellowish hue to it similar to an incandescent light bulb or a wood fireplace. Incandescent lights are enjoyed by many people for their color hue for evening applications where softer light is desired. After all, our ancestors gathered around fires in the early days of civilization. It is not surprising that this color temperature is still admired by humans in relaxing evening situations. Lighting designers should chose 2700 or 3000 degree K lighting color temperatures in these environments if possible.
Daylight applications should use higher color temperatures. In fact, classrooms, hallways, auditoriums, offices, and other work environments should use the 5000 degree lighting color temperature in most instances. This is because it most closely approximates sunlight which wakes us up and keeps us alert similar to what the sun does.
Intermediate applications with dual use day and night lighting should use something in the middle. Retail stores open long hours or even 24 hours may consider a compromise at 4000 degree K. Outdoor security lighting in areas of ambiance should consider 4000 or even 3500 degree K lighting. Outdoor lighting in other areas such as parking lots and garages should stick with the 5000 degree K product. These are not ambiance areas, and so should use the most energy efficient color temperature lighting.
Since LED lighting products use the “Stokes shift” to lengthen wavelength of a large portion of the generated light, and therefore simultaneously lower color temperature, higher color temperatures will always be more energy efficient. It is important to review the various lumens/watt at different color temperatures, and then consider this item as well in making the final specification of color temperature.