occupancy sensors & Lighting

Occupancy sensors are used to ensure lights aren’t left on and to set them on automatically, responding to human presence.

Uses

Occupancy sensors are useful and cheap options for closets and basements, and also for kids’ rooms, bedrooms and laundry rooms… Lights left on can be an energy drain. And that’s when occupancy sensors and other lighting controls make sense: automatically switching or dimming those lights, saves energy and money. With sensors you do not need to switch on or off the lights every time you enter or exit a room or house.

They can also be used in some task lighting applications. In these cases, lights are turned on by the motion of the people working in a specific area (kitchen counter, for instance) and turned off a short period after the work stops.

Occupancy sensors vs. timers

Occupancy sensors can make more sense than timers in many lighting applications due to their flexibility.

The main problem with occupancy sensors is their accuracy in detecting fine motions or heating variations (infrared sensors) or sounds (ultrasonic sensors). An inadequate or poor quality occupancy sensor will not switch the lights on adequately, or be a source of false triggering.

Make sure you choose the right type of occupancy sensor. See: Choosing a sensor.

Timeouts

Some occupancy sensors have timeout options: you can choose, say, 1, 3, 5, 15, 30 minutes timeouts (the exact timeout options vary with models and manufacturers).

Types

Occupancy sensors are typically of three types: ultrasonic, infrared and dual technology (combined multisense technology: ultrasonic and infrared). Ultrasonic sensors detect the presence of people by using sound waves, while the infrared respond to heat and motion.

See: Choosing Occupancy Sensors

Prices

Occupancy sensors are inexpensive or relatively inexpensive, but prices vary significantly: from around $12 to $80 or more. Dual-technology sensors are the most reliable, but also the pricier.

Manufacturers

Andev, Hubbell, Maxxima, Leviton and Lutron are well-known manufacturers of occupancy sensors.

Wireless occupancy sensors

Besides hard-wired occupancy sensors, there are now wireless occupancy sensors (communicating via radio frequency), which have obvious advantages: going wireless eliminates the need for new wiring, which can be costly…

These sensors are easily installed, often in a fraction of an hour…

Location

Occupancy sensors must be strategically located in order to detect people in the room. Otherwise they may not perform adequately. See: Choosing Occupancy Sensors

Compatibility with other controls

Occupancy sensors can be associated to other lighting controls, which raises the question of compatibility. In fact, in such cases, their reliability depends on the quality of the communication with those other controls (dimmers, for instance) and switches, which poses compatibility issues. Typically, only controls and switches from the same manufacturer offer compatibility.