What Is A Glass Break Detector and How Does It Work?

Home security system window and door sensors offer valuable protection: They sound an alarm when the system is activated and an intruder opens the window or door. But what if an intruder broke through the glass instead? Standard sensors wouldn’t pick it up.

Enter a glass break detector, which adds an extra layer of protection to your home. It’s necessary for detecting when the glass on a window or door is broken.

You might consider getting a glass break detector if you have a sliding glass door or easy-to-reach windows (like those on the first floor of your home) and you’re concerned about break-ins. They’re often a good choice for people with large or multi-level homes, or those who are away from their home for periods of time and wouldn’t be able to hear breaking glass.

How Glass Break Detectors Work

A glass break detector communicates with a home security alarm, alerting you and/or emergency services when door or window glass is broken. That way, you can quickly call for help. They’re usually used in conjunction with window and door sensors, so homeowners can stay posted on both unwelcome opening and broken glass.

How a glass break detector works depends on the type you choose: some are equipped with a shock sensor and others work with an acoustic sensor.

Types of Glass Break Detectors

When choosing a glass break detector for your home, consider the type. The two main types differ by how they sense broken glass.

  • Shock glass break alarm: A shock sensor picks up on vibrations caused by broken glass. With a shock detector, a sensor—usually comprised of an electrical wire—needs to be attached directly to each door or window you want to protect. The vibrations break the wire’s electrical current, and set off the alarm.
  • Acoustic glass break alarm: An acoustic sensor uses a tiny microphone to detect the specific frequency of the sound of breaking glass. This might be a good choice if you have a room with several windows and/or doors that you want to protect, since you’ll likely only need one unit per room.

Keep in mind the potential for false alarms. A shock detector could be set off by door slamming or other vibrations, like those from a child bumping into the glass. An acoustic detector could be set off by the sound of a dropped dinner plate or a loud action scene in a movie—but adjusting the device’s sensitivity could help prevent that.

How to Set Up Your Glass Break Detectors

Glass break alarm detectors are usually fairly easy to install and can be a DIY project. However, many times, professional installation is part of a home security alarm purchase.

Step 1: Figure out how many sensors you need.

If you’re getting a shock glass break detector, you’ll need one sensor per window or door. It may need to be placed at a specific area of the window or door to work properly.

For an acoustic glass break alarm, check to see how far of a range of sound your unit has. For example, it may sense the sound of broken glass up to 20 feet away (which is pretty standard). In that case, you’d need enough sensors to have one within 20 feet of each door or window you want to protect. Also, keep in mind that curtains and blinds could muffle the sound a bit, so in some cases, they may need to be even closer. Usually, one acoustic glass break alarm per room is enough, but you may need more for a larger room.

Step 2: Install the sensors.

Carefully follow the instructions that come with your glass break alarm to properly install the sensors. Shock glass break detector sensors will mount directly to windows and doors. Acoustic glass break detector sensors can mount to a wall or ceiling. Remember: it needs to be within a specific distance from each window and door it’s designated to protect.

Step 3: Activate and adjust the sensors.

Activate your sensors and link them up with your security system according to the instructions. Then, you can test them to make sure they’re working properly and adjust them so they’re less likely to set off a false alarm.

If you’re having your sensors professionally installed by your security company, they may do the testing and adjusting for you too.

For a shock glass break detector, you may be able to test by tapping the glass with your finger or a rubber or plastic object. For an acoustic glass break detector, you’ll need a high-pitched noise that resembles glass breaking. Many people simply clap their hands, but there are glass break apps that promise better accuracy by emitting a more similar sound.

While you’re testing, you can adjust the sensors so they can pick up on the vibration or sound you want them to detect. And also decrease the likelihood of false alarms. Then, your glass break alarm detectors will be up and running!

By combining glass break detectors with door and window sensors, you’ll be adding to your home’s protection and equipping it to sense the most common types of break-ins.

This article has been reviewed and approved by Officer Banta.

Officer James Banta

Officer Banta is the official SecurityNerd home security and safety expert. A member of the Biloxi Police Department for over 24 years, Officer Banta reviews all articles before lending his stamp of approval. Click here for more information on Officer Banta and the rest of our team.

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