An occupancy sensor automatically detects human presence in a room or zone to optimize HVAC operation and reduce energy consumption when spaces are unoccupied. Sensors use infrared, ultrasonic, or dual-technology detection to enable demand-controlled ventilation, setpoint adjustments, and equipment scheduling. Modern sensors reduce unnecessary heating and cooling by 10-20% in intermittently occupied spaces.
Sensor Technologies
Passive infrared (PIR) sensors detect body heat with response times of 2-5 seconds and coverage areas up to 800 square feet. Ultrasonic sensors emit high-frequency sound waves to detect motion through small obstructions. Dual-technology sensors combine PIR and ultrasonic to reduce false triggers in areas with air movement or small animals. Time delay settings typically range from 5-30 minutes before returning to unoccupied mode.
Building Integration and Savings
Occupancy sensors trigger outdoor air reduction from 15 CFM per person (occupied) to 5 CFM per person (unoccupied) in intermittent spaces. Applications include conference rooms, classrooms, and retail areas. Integration with building controls enables automatic setpoint changes (adjust to 72°F occupied, 78°F unoccupied) and equipment staging based on real-time occupancy patterns.