Color temperature is measured in degrees Kelvin and refers to the color of light. The yellow light produced by a candle has a very low color temperature of 1,000 degrees Kelvin. As the color temperature increases the yellow disappears, passes through white and arrives at the very high 10,000 degree Kelvin color of a clear blue sky.
Prior to a standardized color temperature measured in degrees kelvin, we used words to describe our growing variety of light colors. Words like warm white, cool white, artic white and soft white became confusing and open to interpretation.. we needed a more scientific approach and a scale.
The scale was developed by heating a specific piece of metal till it glowed the same color as a “warm white” bulb. The actual 2700 degree Kelvin temperature of the metal became the assigned color temperature of the bulb. This scale was then used to develop the “color temperature” for all current and future light bulbs.
This scale has help organize the almost endless color possibilities offered by LED.

2700k – Is the most popular and traditional color temperature in America and offers the greatest variety of bulb shapes and sizes. It creates a cozy and inviting atmosphere and is perfect for most residential and hospitality applications.
3000k – Some prefer it’s slightly whiter color for bathrooms and entry ways. However it is not as widely available as 2700k.
2000k – Very limited. Best suited for lounges, restaurants, bars etc.
4000k and 5000k – These provide a crisp and invigorating ambiance and are common in exterior, commercial and industrial applications.