How Does a Glass Break Detector Work?

Quick answer

There are two types of glass break detectors, both of which offer different advantages and disadvantages:

Acoustic glass break detectors detect the acoustic frequencies of breaking glass and can be placed centrally in a room to monitor multiple windows at once. The downside to these sensors is that they’re more susceptible to false alarms.

Shock sensors are placed directly on window glass and detect physical vibrations. While these sensors are more reliable than their acoustic counterparts, they require one sensor per window, which can lead to higher costs and more tedious setup.

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Types of glass break sensors

There are two basic types of glass break detectors that work in very different ways: acoustic sensors and shock sensors. Here is a quick overview of the advantages and disadvantages of each type of glass break sensor:

  • Acoustic glass break sensors: Acoustic sensors monitor a larger space for the specific frequency emitted by breaking glass. The most significant benefit of these sensors is that one sensor can monitor multiple windows within their range. Frontpoint sensors, for example, can monitor up to 20 feet in any direction. The only downside to acoustic glass break detectors is they’re not as accurate as shock sensors. Some noises are similar enough to the sound of breaking glass that you might get occasional false alarms.
  • Shock sensor glass break detectors: These detectors are placed on the glass so they can detect a direct shock to a window. Although they have a lower chance of false alarms, they require one sensor per window, so you’ll have to spend a little more money buying multiples.

Glass break detectors vs. window sensors

Window sensors and glass break detectors perform very different functions, and you’ll want both to ensure your home is truly secure from break-ins. Window sensors can only determine whether or not a window is opened. If a savvy burglar notices a window sensor on the window, they could break the glass instead of trying to open the window.

However, if you install glass break detectors to back up your window sensors, you’re protecting your windows from every intrusion method.

How to set up glass break detectors

Shock sensor glass break detectors

Shock sensors should be placed directly on the glass about an inch from the corner of the window. Make sure to clean the area beneath your sensor, then attach it to the window with the adhesive strip on the back of the device. You can test its sensitivity by tapping on the opposite corner of the window. If the alarm activates, it will likely go off when the glass is broken.

While shock sensors are less prone to false alarms, they can still happen if, say, a kid or pet bumps into the window. But modern shock sensors are generally reliable, especially compared to acoustic sensors.

Pro Tip
Test the detector before adhering it to the window so you don’t have to replace the adhesive.

Acoustic glass break sensors

You can install most acoustic glass break detectors on a ceiling or wall within range of multiple windows. As we mentioned above, the standard range for these devices is around 20 feet, so you should install your detectors where they can cover the most possible windows.

Start securing your home

Glass break detectors are most effective when used alongside window and door sensors. The three sensors combined can help protect every potential intrusion point in your home. If you’re interested in purchasing glass break detectors these are our top picks.