Technical Explanation: The CRI is a unit that measures the ability of a light source to reproduce the colors of objects faithfully in comparison with an ideal source of light, or natural sources such as sunlight. The CRI is a determined value from 0 to 100, with 100 being the value “perfect” or daylight.
Real World Explanation: The CRI determines how you and your surroundings appear to you and the other people in your environment.
Effective in 2012 all light bulbs are required to have a label similar to this one. You are now able to compare the efficiency of one light bulb to another. In the lighting business this is know as efficacy, the ratio of lumen output to watts consumed. The label also has other valuable information about the light bulb such as color temperature, estimated annual cost and estimated life.
One reason for this new label is to let the consumer make an informed buying decision. Most people have associated watts with light output. Watts are a measure of energy consumed, not a measure of light output. Lumens are a measure of light output.
The label above is from a 13 watt compact fluorescent light bulb while the one to the right is from a 60 watt incandescent light bulb. You will notice that the light output (lumens) is about the same for each but the energy consumed (watts) is dramatically different. The efficacy of the CFL is much better than the incandescent, 67 lumens per watt as compared to about 14 lumens per watt.
I am not advocating one way or the other for either type of light bulb. The label does the talking, you make the decision. Please visit the app store and download “LightSmart”, the free app from UL that has lots of useful lighting information you might enjoy. And please visit FoggLighting.com.