Glass Break Sensors: A Valuable Component of Home Security Systems

When it comes to home security system intrusion sensors, people tend to be most familiar with motion sensors and door and window sensors. Both are essential, and the latter are key components in protecting a home’s perimeter.

But if an intruder enters a home by smashing a glass window instead of opening a window or door, they can potentially slip inside without triggering perimeter alarms. In fact, WPTV News in West Palm Beach Florida interviewed a thief who forced his way into 5,000 homes—and he often did it by breaking through glass patio doors. To protect against this specific threat, those homeowners could have used glass break sensors.

Door and window sensors are only equipped to detect if a door or window (or basically anything else that opens or closes) is opened. However, the best glass break sensors detect the sound of a broken window pane or a shattered glass door anywhere within a 20-foot radius and trigger an alert to the user and an audible alarm.

In this article, we explore the different types of glass break sensors, how they work, and how best to place wireless glass break sensors within your home.

There are two types of glass break sensors: acoustic and shock. Although they work differently, they will both detect broken glass and can set off a home security alarm if they are triggered.

When a pane of glass shatters, it creates a very distinct sound frequency. An acoustic glass break sensor works by “hearing” this sound of shattering glass. They have a fairly wide range (within about 20 feet of the glass) and wireless models can communicate with a security system control panel that is placed within 100 feet of a sensor. That means that a single acoustic glass break sensor can often protect most or all of the windows and glass doors within an average-sized room.

Shock glass break sensors work by “feeling” the unique vibrations of shattering glass. To function properly, they must be physically attached to the window or glass door that they are protecting.

Although shock sensors may trigger fewer false alarms than acoustic sensors, they have significant drawbacks. For example, with shock sensors, you need to mount a sensor on each window and glass door that you wish to monitor. This can get expensive and be difficult to set up properly. Also, modern acoustic sensors can specifically distinguish the routine sounds of broken glass—like the cat knocking a drink off of the counter—from the noise made by a shattered door or window, minimizing false alarms.

For this reason, Frontpoint’s comprehensive home security system uses acoustic glass break sensors to minimize costs, simplify installation, and keep your home safer.

Door and window sensors and motion sensors are fundamental parts of a home security system. However, there are some situations where they alone are not the most effective tools against home invasion.

If an intruder enters your home by breaking a large window or glass door and stepping through the opening they’ve created, door or window sensors will not trigger your alarm system because the door or window frame remains closed.

And if you have a motion sensor installed, the intruder may have a chance to survey your home’s interior before entering, allowing them to spot, and potentially avoid, the device if you don’t have other motion sensors in certain areas of your residence.

A glass break sensor can fill these coverage gaps.

For example, glass break sensors can be particularly useful for homeowners who have set their motion sensors at higher levels to avoid having them tripped by large pets, or for individuals who prefer to deactivate their motion sensors at night so that they’re not triggered by people heading to the kitchen for a late-night glass of water.

As the only commonly used home security sensors activated by sound, acoustic glass break sensors present a unique challenge for burglars and add an extra layer of protection. They can also be a cost-effective home security solution for large rooms with multiple windows and sliding glass doors.

If you can’t afford door and window sensors for every entry point in a room, one glass break sensor can provide protection for all of the panes of glass within that unobstructed 20-foot range. And again, if that glass entry point is big enough to shatter and then enter without opening a door or window, the door and window sensors alone won’t detect the intrusion.

Of course, for the most comprehensive protection against home invasion and burglary in certain residences, you may want to install door and window sensors, motion sensors, and glass break sensors.

An ideal setup for acoustic glass break sensors is placing them within range of any window or glass door that a burglar could fit through. Breaking door or window glass is one of the most common methods of entry for household burglars. Even second-story glass openings could be protected by glass break sensors if they’re near a tree or another relatively easy method of access.

Glass break sensors use microphones to listen for the specific sound of shattering glass with their unobstructed range; thus, they are not able to pick up sound frequencies that are muffled by walls or other large items between the glass and the sensor. For this reason, you will need to install separate sensors in each room that you would like to protect with this technology.

Frontpoint’s Glass Break Sensors are also designed to detect only the specific sound frequency emitted when panel-type window or door glass is broken. You don’t need to worry about setting them off by accidentally dropping a glass in the kitchen or watching a TV show that contains the sound of breaking glass. You can install Frontpoint’s Glass Break Sensors in any room of your home without worrying about these types of false alarms.

Step One: Consider which windows are most easily accessible from outside of your home and which are large enough to allow a burglar to enter. Also look for windows that, if broken, could allow a burglar to reach in and unlock an exterior door. Those are the windows you most want to protect. All large fully glass doors should ideally also be protected by glass break sensors.

Step Two: Decide how to distribute your sensors. You want to use as few sensors as possible to cover as many windows and/or doors as possible. Areas with multiple windows are a natural starting point. For example, if you have an average-sized room with several windows and a sliding glass door, you may be able to protect the whole room with a single sensor. Again, acoustic glass break sensors have approximately a 20-foot radius.

Step Three: Sensors need at least 4 feet of range from the glass. Select a location 4 to 20 feet from the window(s) or door(s) you’d like to protect. Ensure that the sensor will have a clear line of sight to the glass. This location also needs to be within 100 feet of your Frontpoint Hub to ensure proper wireless communication with the security system. This distance can go through walls; the sensor only needs a line of sight on the glass, not the Hub.

Step Four: If you’re adhering the glass break sensor to a flat wall or ceiling, make sure the mounting surface is clean and dry. Remove the wax backing from the adhesive pads and press and hold the sensor firmly against the wall or ceiling for 30 seconds. The sensor can also be placed on a table or shelf.

It’s important to have a variety of security sensors within your home security system, though glass break sensors aren't necessary for certain residences.

If you live on a high floor in a multistory condo with a single point of entry, for example, a glass break sensor probably isn’t going to be needed. But in homes that have multiple potential entry and exit points for intruders—many of which are composed of glass—these devices play an important role. Each different type of intrusion sensor has its part to play in home security, protecting your residence with complementary, concentric layers of detection.

Frontpoint keeps homes safe whether families are there or not. We've been revolutionizing the home security industry for over a decade. And we're just getting started. To shop DIY home security systems, check out our Security Packages. If you have questions or would like to discuss a quote, contact us at 1-877-602-5276.