How Well Do Passive Infrared Security Systems Work?

Function

• Passive infrared security systems are considered a type of interior motion sensor that can detect the presence of an intruder that is already moving within a protected boundary. A passive infrared sensor installed in an interior hallway in front of a door would be an example of an interior motion sensor used in a home security system, as it would detect movement upon unauthorized entry through the door.

Benefits

• Passive infrared security systems can be mounted on ceilings or high on interior perimeter walls to achieve a 360-degree intruder detection pattern. Passive infrared security systems can be utilized with other intruder detection technologies such as as an ultrasonic sensor to provide a seamless security solution for a number of environments.

Considerations

• Because passive infrared sensors rely on changes on temperature between a "hot" subject and a "cool" background to trigger an alarm, the sensor can become less effective should the secured space reach the same temperature as an intruder.