Time switches for lighting, fans and equipment: Intermatic 24-hour mechanical timers, spring-wound interval timers, plug-in timers and heavy-duty outdoor timers, alongside Leviton Decora and Lutron Maestro in-wall timers and Prime digital countdown timers. The first split is plug-in versus in-wall — plug-in units need no wiring, while in-wall units replace a switch and most digital models need a neutral in the box. Mechanical dial timers repeat the same on/off pattern every day and hold their setting through a power failure; digital timers do more but lose the program in a long outage unless they have battery backup. A spring-wound timer is the right answer for an exhaust fan or a heater somebody will otherwise leave running all night.
