CFL Facts and Myths2

• What are Pin-Base CFLs?
Pin-base CFLs have small plastic bases with 2 or 4 pins that each have a diameter of about 0.1
inches. The base does not contain a ballast. Pin-base CFLs are designed to be used with
separate ballasts that are mounted in special fixtures designed for pin-base CFLs. For us ,
these have been almost completely replaced by GU24 Sockets
• What is a GU24 socket?
The GU24 socket and base system is designed to replace the Edison socket and base in energy
efficient lighting fixtures. The Energy Star program requirements for residential lighting
fixtures, Version 4.0 require that residential lighting fixtures cannot use the standard Edison
screw base, even if they do not have a built-in ballast. The same requirement is included in
California’s energy efficiency standards for residential and nonresidential buildings, known as
Title 24. This requirement is designed to insure that fixtures that receive Energy Star qualification cannot be operated with an incandescent bulb. The GU24 socket was designed to be
compatible with these energy
efficiency regulations.
CFLs with a GU24 base are designed to be connected directly to the power line, so they are
functionally equivalent to screw-base CFLs instead of pin-base CFLs. Unfortunately, Energy
Star refers to CFLs with the GU24 base as self-ballasted pin base lamps, a designation that
may lead to some confusion with pin-base CFLs that do not have an integral ballast. Some
manufacturers are also making modular ballasts with a GU24 base on one end and a socket for
a pin based CFL on the other. These modular ballasts can be used to adapt normal pin-base
CFLs to fixtures that have the GU24 socket, therefore reducing the amount of
material that must be thrown away when the lamp fails.
• Can dimmers work on CFLs?
Most screw-base CFLs do not work with dimmers designed for use with incandescent bulbs.
These CFLs will have a label on the bulb and/or the packaging stating “not for use with dimmers”. However, certain special screw-base CFLs are designed to work with standard incandescent lamp dimmers. These CFLs will be labeled “dimmable” or similar language on the lamp
and/or the packaging. Due to small differences between different brands of dimmers, not all
dimmable CFLs work with all types of incandescent dimmers.