Published on September 2nd, 2014 | by Peter Young


A Guide To Understanding Modern Light Bulbs: Color And Temperature

9light bulb colors

When it comes to modern light bulbs, being able to understand and choose the proper color and temperature is just as important as using the right style and shape of light bulb. To help give you a better idea of how to determine which color and temperature is right for you, we’ve come up with the following guide.

A Guide To Understanding Modern Light Bulbs: Color And Temperature

Most light bulbs today will come in a variety of colors and temperatures, and these are determined by measuring the light bulb’s light by a unit known as a Kelvin. For practical purposes, this is best understood as an absolute measure of temperature, and is expressed as a unit of K. The following image will help to give you a better understanding of where the different colors and temperatures fall in the spectrum:

temp. chart

As you can see, the blue colors of light are the hottest and come in around 5000K, while the red colors are the coolest and come in around 2,200K. A good way to think about light temperature in this spectrum is to compare it to a flame. If you’re looking at a flame the middle of it should appear almost blue, and is the hottest part of the flame. The further out from the center you go, the color fades into yellows and reds, which are the coolest parts of the flame. The video below will help to elucidate this seeming contradiction.

Check out this video to get a better idea of how this scale works, and where the different colors and temperatures fall within it (feel free to skip over the color rendering index parts if you’d like):

All manufacturers will use a measurement based on the Kelvin (K) scale when determining the color and temperature of their light bulbs, and this measurement will always appear on the packaging. Generally speaking, there are three different color and temperature ranges that you’ll find in use around your home:

  • Soft White or Warm White 2,700k – 3,000k
  • Bright White or Cool White 3,000k – 4,800k
  • Daylight or “Hospital” White 5,000k +

It is important to note that not all light bulb manufacturers will use the same terminology when classifying the color and temperature of their light bulbs. For this reason we recommend that you go by the light bulb’s Kelvin rating, rather than its name. This will help to ensure you get the color and temperature of light you prefer.

All of these colors and temperatures will have different uses around your home and it’s important that the right colored light bulb be used in the appropriate room. Generally, we recommend the following uses:

  • Soft White – Cool White (living rooms, home office, bedrooms and laundry rooms)
  • Daylight or Hospital White (security lights and patios)

Ultimately, the choice of which color and temperature of light bulb you use (and where you use it) is up to you. However, we have noticed that many people have been turned off from “efficient” light bulbs because they installed a color of light bulb that wasn’t to their liking. Just remember, energy efficient light bulbs come in a variety of colors and temperatures.

If you want to learn more about light bulbs, check out this article on the various light bulb shapes and sizes. Also, be sure to check out some of our green home improvement projects: Green Living Ideas, after all, is a top 20 home improvement website!

Photo courtesy of Super Bright LEDs, Bravo Light,

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About the Author

graduated from Pacific Lutheran University (PLU) with a degree in journalism and has made sustainability and eco-conscious living mainstays of both his professional and personal life. It was during his time at PLU that he began his journey with sustainability and it's what has led him to writing for Green Living Ideas. He currently resides in Honolulu and works for Pono Home, an energy efficiency company focused on reducing carbon emissions and promoting a healthier, greener lifestyle.

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