What are the benefits of Glass Break sensors vs Shock Sensors? Should I use both or is one just as good as the other?
That is certainly an interesting question. They are both useful in different ways but can achieve similar desired effects. One is not necessarily better than the other as it really depends on a variety of factors. Some questions to think about:
- Do the windows you’re trying to cover open or are they stationary?
- Do you have a large amount of windows that need coverage?
- How many panes of glass does each window have?
Glass Break Senor
A Glass break Sensor, such as the QS1431 here, is constantly “listening” for the audio frequency of glass breaking. This can be very useful as you can cover an area with multiple windows using just one glass break sensor.
The Glass break detector does have some drawbacks though. There are range limits and it requires line of sight to the window it is meant to cover. They are also more prone to false triggers. While it is listening for a particular frequency akin to glass breaking, it can not differentiate sounds that might fall on that same frequency range. Additionally, if the window is more likely to be opened to gain entry into the home, the glass break wont trigger the alarm, so you will want to use them in conjunction with a door/window sensor on your windows.
Shock Sensor
Shock sensors are usually mounted directly on the glass or frame and, as such, can typically only cover one window at a time. An example of a shock sensor is the PG9935. This combination sensor can then detect glass breaking within its manufacturer’s stated range, as well as if the window is open or closed.
Would a window with multiple panes like this require more than one sensor? What about the patio door?
In general, a shock is going to detect vibration in a certain range from where it is mounted. That range is dependent on the model in use, as well as the material its mounted on and the size of the point of ingress being monitored.
For example, the linked PowerG shock (pg9935) covers a door roughly 7 to 8 feet in height 1 to 4 ft wide and all glass that fits within that size range, depending on thickness.
In the above image, one shock may cover the whole of the window and two to four for the sliding door. Keep in mind the sensor may be too big to be mounted on the stationary portion of the sliding door to not hinder the door being opened fully.
Always follow printed instructions for mounting and testing before relying on the sensor you are installing.