How Well Do Passive Infrared Security Systems Work?

Passive infrared sensors protect your property by using technology that senses temperature differences between a controlled space and heat emitted by human movement. It has proved to be an effective form of property security.

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.

References

• EC&M: Occupancy Sensors 101
• United States Department of Environmental Protection: Interior Intrusion Sensors

Resources

• Entrepreneur: The First Line of Defense - Perimeter Protection