The Air Duct Sensor segmentation by application distinguishes five primary end‑use categories that collectively shape market dynamics. Residential HVAC accounts for roughly 40 % of total deployments, driven by building‑automation upgrades and energy‑efficiency mandates in single‑family homes. Commercial HVAC follows with an estimated 30 % share, reflecting extensive sensor integration in office towers, retail complexes, and hospitality venues where precise airflow control reduces operational costs. Industrial process control represents about 15 % of the market, where duct sensors monitor high‑volume ventilation systems in manufacturing plants, chemical processing, and pharmaceutical facilities to ensure safety and compliance. Automotive HVAC contributes near 10 %, as modern vehicles incorporate duct sensors for cabin climate regulation and passenger comfort. The remaining 5 % comprises data‑center cooling and niche applications such as aerospace and marine environments, where specialized sensor suites maintain stringent temperature and humidity thresholds. Together, these application segments define the overall market size, with each proportion reflecting distinct regulatory pressures, ROI expectations, and technology adoption rates.