CFL stands for compact fluorescent lamp, and it is a small fluorescent light bulb that uses 75% less energy than a traditional incandescent bulb and can be screwed into a regular light socket. Don't let the fact that it is fluorescent turn you off! ENERGY STAR qualified CFLs must pass extensive testing to ensure they produce only the highest quality light. Qualified bulbs labeled "warm white" or "soft white" produce light like typical incandescent light bulbs. CFLs that have a cooler color (similar to bright white incandescent bulbs) are usually labeled "bright white" or "daylight" on the product packaging. More on choosing the right CFL color for you.