Lighting Cooling Index (LCI)

The Lighting Cooling Index (LCI) is a measure of the coolness of a light source. This index helps determine the color temperature of light sources, which is essential for creating the desired ambiance in a room.

What is color temperature?

Color temperature, measured in Kelvin (K) , describes the color of light emitted by a light source:

  • Below 2000K : Very warm, similar to candlelight.
  • 2000K - 3000K : Warm white, like traditional incandescent bulbs.
  • 3000K - 4500K : Neutral white, suitable for workspaces.
  • 4500K - 6500K : Cool white to daylight, ideal for kitchens and workplaces.
  • Higher than 6500K : Very cool, bluish light.

A high color temperature (above 4500K) results in a cooler appearance , while a low color temperature (below 3000K) gives a warmer appearance .

Application of the Lighting Cooling Index

Understanding the LCI is crucial when selecting lighting for different environments:

  • Living rooms and bedrooms : Warmer light sources (below 3000K) promote relaxation and comfort.
  • Kitchens and workspaces : Neutral to cooler light sources (3000K – 4500K) improve visibility and concentration.
  • Offices and commercial spaces : Cooler light sources (above 4500K) can increase productivity.

By choosing the right colour temperature based on the LCI, the desired atmosphere and functionality of a room can be effectively achieved.