- When someone enters a room, it is said to be occupied.
- When a room is vacant, it is said to be vacant.
- Ambient light—the quantity of natural light that enters the room.
The better systems also allow you to program lighting timers and schedules, as well as override any automatic operations.
- Allow significant savings on energy bills
- Cheap and simple to install, particularly wireless systems
- Convenient—lights switched on automatically when needed
- Long battery life due to their low power consumption
- Help with health and safety requirements (e.g. lighting in corridors)