A 23-watt compact florescent light bulb replaces a 100-watt bulb with a standard-sized base. The 23-watt lamp produces approximately the same amount of light and use less than one-quarter of the energy. CFL bulbs have a lifespan of up to nine years, but they contain a small amount of mercury.
Most CFL lamps do not carry an outdoor use rating and do not start if the temperature is too cold. Some CFL lamps are not compatible with older dimmer switches or lamps with three-way switches. Repeated power surges, such as those that occur in a workshop, significantly reduce the life expectancy of the bulb. Choose lamps designed for the specific application when selecting CFL bulbs for these uses.