Can sunlight cause a PIR false alarm?

• A. No
• B. Only with outdoor sensors
• C. It can only cause false alarms in older models
• D. Yes, heat sources including sunlight can cause PIR false alarms

Answer: (D)

PIR detectors respond to changes in infrared heat in their view. Sunlight is a powerful heat source, and when it heats surfaces or moves across an area in front of the sensor, the infrared energy inside the sensor’s field can change rapidly. The sensor interprets that change as a moving warm object, which can trigger a false alarm. This can happen indoors or outdoors and isn’t limited to older models. So heat sources, including sunlight, can indeed cause PIR false alarms. To reduce this, avoid placing sensors where they’ll be hit by direct sun or heat sources, and consider dual-technology sensors that use an additional detection method to confirm true motion.