Energy management systems typically rely on room occupancy data: when the room is not occupied, the temperature can drift, lights can turn off.
EMS devices like thermostats feature PIR sensors to determine occupancy. PIR sensors can detect two things: heat and motion.
In the middle of the night, when guests are fast asleep, PIR sensors still detect heat, but there is very little motion to detect.
Even PIR sensors calibrated to extreme sensitivity can benefit from knowing whether it’s day or night.
Let’s say you’re spending the night in a hotel that senses occupancy ONLY using the PIR sensor.
It’s the middle of the night. Your thermostat PIR sensor detects no heat or movement for a set period of time, like 30 minutes. Based on this data, the occupancy sensor determines your room to be unoccupied, and the temperature drifts away from setpoint. You awaken to a hot room in which the A/C has been turned off. You’re hot and sweaty and generally NOT pleased. The front desk gets an earful from you.
Meet PIR’s sister from a different mister: the light level sensor.
Now pretend you’re in that very same scenario, except the thermostat features a light level sensor in addition to the heat/motion sensor. Your thermostat detects no heat or movement for that defined 30 minutes just like in the previous scenario, but before allowing the temperature to drift it consults one additional piece of data: light level in the room. If the light level is low, it could indicate nighttime and sleeping guests, and so it extends the set period of time to detect occupancy, allowing extra time to detect heat or movement. After this extended time, if no heat or motion is detected, THEN the temperature is allowed to drift.
Not all occupancy detectors feature light level sensors. Inquire about them when you’re shopping for a new EMS.
Discover Telkonet’s entire family of energy management products, including our thermostats featuring the sister duo: the PIR and light level sensor.
Download our whitepaper, Occupancy Sensing Improves Hospitality.
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