# Classroom occupancy sensors



## MDShunk (Jan 7, 2007)

I ONLY use the combination occupancy sensors, regardless of where they're being used. I have found the square foot data to be fairly accurate for the brands I use. I only use Watt Stopper brand, which are also resold under the P&S label (same item). They seem to be the most reliable I've found. I really don't think you're going to have any problems if you use a combo sensor. I happen to have just bought one for an office building hallway, and my invoice for the sensor, relay, and a few boxes came to $174.11.


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## JayH (Nov 13, 2009)

ElectricBill said:


> I am looking for a little advice on how many sensor per classroom and the type of sensors to use in an elementary school environment. Classrooms are about 30'x40', drop ceiling height about 10' and have suspended t8 fixtures about 8'. Air handler vents located under windows. Ideally I was hoping to get by with one sensor located near the center of the ceiling. Published specs seem to argue for more per classroom but, I can never imagine elementary kids sitting still long enough to be a problem. I've read on one vendor's site a recommendation to use combo Ultrasonic, PIR sensors for a school but I wonder if they really are needed they are pricey. Would the hanging fixtures block the IR sufficiently to be a problem? Any advice? Thanks.


Stay within the manufacturer's recommendations (they're pretty accurate) and limit your call backs.


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## jamiewilson3 (Jan 4, 2010)

MDShunk said:


> I ONLY use the combination occupancy sensors, regardless of where they're being used. I have found the square foot data to be fairly accurate for the brands I use. I only use Watt Stopper brand, which are also resold under the P&S label (same item). They seem to be the most reliable I've found. I really don't think you're going to have any problems if you use a combo sensor. I happen to have just bought one for an office building hallway, and my invoice for the sensor, relay, and a few boxes came to $174.11.


I have seen that many keep a wall switch wired in parallel to provide a manual override. Is it OK to wire the switch in series? i.e. if the sensor failed to function, it would mean the lights would not come on. The other draw back being that people could override and there would not be any benefit.


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## frank (Feb 6, 2007)

I have used suspended and reccessed fitings that have a sensor fitted as standard. Makes the overall cost a bit more but you can be sure to have better lighting control

Frank


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## allwiresystems (Nov 6, 2007)

*keep low your call back*

We use in the past Watt Stopper brand and we never have any problems. Check with manufacturer's recommendations for specific project.


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