Motion Sensors 101: PIR vs Microwave vs Dual-Tech Explained

Passive Infrared sensors detect the heat signature of a moving body, and are the most common, lowest-cost motion sensor type. They work well indoors but are prone to false triggers from sunlight, heat sources, or pets, and struggle in environments with rapid temperature swings.

Microwave sensors detect motion by measuring reflected radio waves, and can sense through certain materials (thin walls, glass) that would block a PIR sensor entirely. This wider, more penetrating detection range can be an advantage or a liability — it can also mean picking up motion from an adjacent room or outside a window unintentionally.

Dual-tech sensors combine both PIR and microwave detection, and typically only trigger when both technologies agree motion occurred — significantly reducing false alarms compared to either technology alone. They cost more, which is why they're usually reserved for areas where false triggers are a genuine, recurring nuisance rather than applied everywhere by default.