How do I choose the right compact fluorescent lamp?
To choose the right size compact fluorescent lamp (CFL) as a replacement for your incandescent bulbs, simply compare the CFL’s measurements to the widest portion and the complete height (including the base or pin) of your existing bulb. Pay special attention to the measurement of the narrowest portion of your existing fixture, such as the narrow portion of the harp in a table lamp. To select the right lamp for your application, replace your used incandescent bulb with a CFL of equivalent wattage. The table below shows that in general a 3.5:1 ratio of incandescent to compact fluorescent wattage provides about the same light. CFL manufacturers generally indicate this information on the packaging with wording such as “Equivalent to a 60-watt bulb.