Brightness is measured in lumens; the higher the lumens, the brighter the bulb. Color rendering index (CRI) is a measurement on a scale of 0-100 of how accurately the light from a bulb represents an object's true colors; the higher the number, the more natural the colors appear. Any CRI value over 80 will show colors true to life. Bulbs with a warm light appearance have yellow tones. Bulbs with a neutral light appearance are often used in workspaces. Bulbs with a cool light appearance have white/blue tones and are good for inspecting. A bulb’s estimated yearly cost is based on 3 hours of usage per day at $0.11 per kWh.

LED bulbs last longer and are more efficient than fluorescent bulbs. They generate little heat and withstand vibration. To install, bypass the ballast by wiring the socket directly to the power source.

Fluorescent bulbs are energy efficient, but they contain small amounts of mercury (for disposal information, visit www.epa.gov/cfl). Plastic-coated glass bulbs are shatter resistant; the coating retains glass shards if they break.

Bulbs that cannot be sold to Canada exceed local regulatory limits on mercury. Bulbs that cannot be sold to CO, DC, HI, MA, NJ, and VT do not meet local energy efficiency regulations.