ENERGY STAR qualified CFLs can produce varying shades of white light. The shade of white light is identified by the correlated color temperature or CCT, which is measured in kelvin (K).
Lower kelvin numbers mean the light has a warmer color, while higher Kelvin numbers mean the light has a cooler color.
The majority of CFLs available in the market offer soft or warm white light (2700K–3000K), which is comparable to an incandescent bulb.
This color range works well in most residential settings and enhances warmer colors (red, yellow, orange) found in your home.
Qualified CFLs are also available in higher kelvin color temperature CFLs (3500K, 4100K, 5000K, 6500K) and will emit more white to bluish-white light. These products are usually identified with the terms "bright white," "natural" or "daylight."
These colors will enhance cooler colors (blue, green, violet) in your home.