Qolsys IQ Glass-S glass break sensor placement

The installation manual for the Qolsys IQ Glass-S glass break sensor does not mention any placement restrictions regarding air vents. I recall the Honeywell sensors on my old 2Gig system specifying placement away from air vents. Is there a similar but undocumented requirement for Qolsys glass break sensors or is this not a concern?

In context, the place in the room that is nearest the center of all glass being monitored is on the ceiling within several inches of an HVAC intake vent. The second best place in the room is within a foot or so of the same intake vent but on a wall. The third option is away from the intake vent but it is considerably off-center of the glass. Thoughts?


You might be referring to motion detectors, those shouldn’t be placed near HVAC vents. Maybe? I know the glass sensors (as part of their algorithm to detect glass breakage) is to listen to certain frequencies. As long as the sensor is within the operating conditions, it should be ok. I can see your concern as a few inches is close but you mention its an intake and not a vent, that would be better than blowing hot/cold air on it (if it has any effect on it).

That is more of a concern for Motion Detector. A glass break detector is an audio detector, air flow is not going to cause an issue. It needs line of sight to the glass and the glass must be within the physical range.

You shouldn’t have issues near an air return.

I finally located the docs for the old sensor by Honeywell. It cautions against installing within 1M of a forced air vent. No idea why, older tech maybe. But since this does not appear to be a concern for the Qolsys sensor I will use the best physical location and not worry about the proximity to the intake.

Thanks for the guidance.

I’m not seeing that in the 5853 manual, but I am not sure if that is the model you are referencing. In any case, that is going to be referencing potential vibration or noise coming from the air vent/HVAC.

The IQ sensor does not call that out, and I would not expect any issues from an air return like you are describing.

Yes, that’s it. It is in the FlexGuard 5853 Installation Manual. I am pasting the snip here just to document it. But I agree that since I am using the Qolsys sensor now and it has no similar restriction mentioned then I can just use optimal placement.