In many places of work, or areas with erratic occupancy, lights are needlessly left on when rooms are unoccupied. Occupancy sensors work by using infra-red to detect the presence of people and then switch the lights off when the room empties and lighting is not required.
These occupancy and vacancy sensors reduce energy consumption in building spaces by automatically shutting off the lights during periods of non-use. You never have to worry about turning on or off the lights. The sensors will automatically turn them on and off when you enter or exit a restroom, a classroom, a conference room, a hallway, or your office. Using occupancy and vacancy sensors can eliminate between 20 and 80% of lighting energy costs.
To make sure that the PIR detector does not plunge rooms into darkness, it is important to ensure the whole area requiring light is covered. For example the “zone” covered by a single PIR is 5 metres diameter strong detection with a 7 metre secondary detection zone which will detect a person walking into or out of the area.
Occupancy sensors are "application-sensitive" devices, meaning that most problems in the field are the result of misapplication. When considering occupancy sensors you should take into account the following.
Manufacturers are constantly researching and developing new technologies that will improve many aspects of performance such as adjusting sensitivity automatically and being resistant to false triggering due to airflow, coverage fluctuations due to temperature and humidity and blackouts caused by coverage gaps.
Every manufacturer wants to be the best and build additional value into their products. We as consumers can only benefit from their findings and innovative design improvements.