How to Compare the Color Temperature of Light Bulbs

Light bulbs vary in color temperature. Some bulbs give off a crisp, white light, while others emit a warm, yellowish glow. In order to determine and compare the color temperature of light bulbs, pay close attention to the labels.

Warm v. Cool

• The Kelvin (K) scale measures the color temperature of a light. Color temperature describes the appearance of the light emitted, not the heat output. Lights with "cool" color temperatures emit a blue-tinted light; those with "warm" color temperatures emit a red-tinted light.

Light Bulb Labels

• Check the label of the bulb to determine the appearance of the light emitted. A color temperature of 3,200 K or lower has a warm appearance; a color temperature of 4,000 K or higher has a cool appearance. Basically, as the color temperature increases, the color of light appears less yellow and more white. When the temperature reaches 5,000 K or higher, the light appears bluish-white.

Color Temperature Reference Points

• Candlelight's has a color temperature of 1,850 K.

  A standard incandescent bulb's color temperature falls in the range between 2,700 K and 2,800 K.

  Fluorescent bulbs have more of a range depending on which model you select: A warm-white fluorescent bulb comes in at 3,000 K; a neutral-white fluorescent bulb, 3,500 K; and a cool-white fluorescent bulb, 4,100 K.

  On a bright day at noon, the sun has color temperature of 5, 400 K.