Light Bulbs and Color Temperature

With the introduction of the new energy-efficient light bulbs, you may have noticed that today’s light bulbs vary significantly by color temperature.

The color temperature of light bulbs is something we’ve always taken for granted because there were not multiple kinds of light bulbs available. In the past, there was only the incandescent light bulb, which emits a specific color temperature.

What is color temperature and how does it affect the lighting in our homes?

“Color temperature is what you see when you look at a neutral surface illuminated by a light bulb,” says Terry McGowan, FIES, LC, director of engineering and technology for the American Lighting Association. “Your eye tells you immediately whether the light is visually cool, warm or somewhere in between. That sense of visual warmth or coolness becomes part of your perception of the illuminated space.”

The usual measure of color temperature is the Kelvin scale, abbreviated as “K,” where 2700 or 3000 Kelvins is described as warm, 3500 Kelvins is neutral and higher Kelvin values are cool.

“Since we have used incandescent light bulbs for residential lighting for more than 130 years, there is a definite consumer preference for light bulb color temperatures of around 2700 Kelvins, which is the color temperature of standard incandescent light bulbs,” McGowan says. “This is the color temperature of that familiar, warm-colored light to which we are accustomed in our homes.”

While standard incandescent bulbs typically have color temperatures of about 2700 Kelvins, the new halogen incandescent bulbs are closer to 2800 Kelvins.

“When compact fluorescent light bulbs or CFLs and LED light bulbs came along, there is now a broader choice of light bulb color temperatures because manufacturers can easily make them,” McGowan adds.  “The color temperature scale is the same for all light bulbs. A 3000 Kelvin incandescent light bulb has the same degree of visual warmth or coolness as a 3000 Kelvin CFL or LED light bulb.”

What’s the best color temperature for home lighting? That depends on personal preference and also which room you are lighting. For instance, you may want a warmer 2700 Kelvin light bulb in the bedroom and a cooler 4000 Kelvin light bulb in the bathroom.

To see how the color temperature of lighting affects your home’s mood, check out the ENERGY STAR Choose a Light Bulb Guide.

Light Bulbs, Lighting Design