There are several different types of lightbulbs that can be used in ceiling lights, including incandescent bulbs, CFLs (compact fluorescent lamps), and LED (light-emitting diode) bulbs. Incandescent bulbs are the traditional type of lightbulb and use a filament that is heated by electricity to produce light. CFLs contain mercury vapor and use less energy than incandescent bulbs, but they take a few minutes to reach full brightness. LED bulbs are the most energy-efficient type of lightbulb and last much longer than incandescent or CFL bulbs.