How Does a Glass Break Detector Work?

SafeWise is an independent review site. We may earn money when you click links on our site. Learn how we rank and review.

Door and window sensors sound an alarm when someone opens a door or window to your home. But if a burglar were to break into your home by smashing a window—instead of forcing it open—the window sensor wouldn’t trigger.

Glass break detectors complement door and window sensors by monitoring sound or vibration. When they detect the frequency or shock waves associated with glass shattering, they sound an alarm. These devices are great additions to home security because they can remain armed all the time, unlike motion detectors, which must be turned off when you or your family are at home.

Here’s a closer look at the technology that makes these window break alarms work.

Protect your property
Sign up for our weekly newsletter to get the latest deals, home security tips, and in-depth reviews.

By signing up, you agree to our Terms and Conditions and Privacy Policy.

The science behind glass break sensors

Glass break detectors are ideal to use in rooms with large windows and sliding doors. The detector is a small device you attach on or near your windows. Like a motion sensor, the range is limited, so you’ll likely want multiple glass break detectors for your home.

There are two main types of glass break alarms. The first type features shock sensors, which monitor for the vibrations of breaking glass. These are generally mounted directly on the windows they’re monitoring. It’s worth noting that these types of detectors can sometimes set off false alarms, as a door slamming could mimic the same vibrations of glass breaking.

If you’re worried about false alarms, you can opt for a glass break detector that relies on acoustic sensors instead. A small microphone listens for the specific frequencies of breaking glass. If a burglar were to break through a window, the detector would pick up on the high-pitched shattering sound to trip the alarm.

Adjusting device sensitivity

When considering glass break detectors, many people worry about triggering false alarms if they accidentally break a glass plate or are watching an action movie. Potential false alarms are why you should test and adjust sensitivity levels when you first install your glass break detectors.

The testing process will differ depending on the detector you purchase, but most have a “test” button. When testing, you’ll clap your hands loudly near your windows. You can also play a video of glass sounds for greater accuracy.

Even after testing, there’s always the chance of a false alarm, so you may want to avoid placing glass break detectors in the kitchen or near your television, where other shattering noises are likely to be loudest.

Wondering what home security companies offer glass break detectors? Check out the packages offered by our top home security company picks to find out.


Compare the best home security systems

Brand
Best for
Monthly cost Icon Tooltip  Dark
Starter equipment price
Contract required
Smart home compatibility Icon Tooltip  Dark
Learn more
Read review
Best overall$599.00
Icon Yes  LightNo *
Amazon,
Google,
Z-Wave
Budget pick$245.00
Icon Yes  LightNo
Amazon,
Google
Most experienced$0.00
Icon No  LightYes
Amazon,
Google,
Z-Wave
Best customer experienceQuote required
Icon Yes  LightNo
Amazon, Google
Best optional monitoring$199.15
Icon Yes  LightNo
Amazon,
Google,
Z-Wave

Info current as of post date. Offers and availability may vary by location and are subject to change.
Full ADT disclaimer

Celeste Tholen
Written by
Celeste Tholen
Celeste has dedicated her decade-long career to reporting and reviews that help people make well-informed decisions. She oversees editorial strategy and production for SafeWise, with a goal to help everyone find the information they need to make their homes and lives safer. Prior to SafeWise, she worked as an editor and reporter for KSL and Deseret News. She holds a Bachelor's degree in Journalism. In her free time, she volunteers at the local botanical garden and writers for the community newspaper.

Recent Articles

The Best Google Home Security Systems
Find out why Vivint is the best security system that works with Google Assistant—and see...
Abode, Frontpoint, ADT Safestreets logos as alternatives for Vivint
Alternatives to Vivint
Vivint isn’t for everyone. We researched and found three other home security systems to better...
Mother looking at security system app with family
The Best Home Security System Apps
Home security apps help you protect your home when you’re not there by letting you...
diy-security-system-on-ipad
Best DIY Home Security Systems of 2023
SimpliSafe is the best DIY home security system because it's cost-efficient, effective, and easy to...