CFLs perform best in open fixtures that allow airflow, such as table and floor lamps, wall sconces, pendants, and outdoor fixtures. For recessed fixtures, it is better to use a reflector CFL than a spiral CFL since the design of the reflector evenly distributes the light down to your task area. If a light fixture is connected to a dimmer or three-way socket fixture, you'll need to use a special ENERGY STAR qualified CFL designed to work in these applications. Make sure to look for CFLs that specify use with dimmers or three-way fixtures.