Motion Detector vs. Window Sensor: Pros and Cons


September 1, 2020

1 44 motion-detector-vs-window-sensor-pros-and-cons Desktop

When installing your security system, should you invest in a motion detector or a window sensor? In many situations you should  have both,  but that doesn’t mean you shouldn’t explore your options in different areas. Let’s compare the pros and cons of motion detectors and window sensors.  

Motion Detectors 

Motion detectors use various technologies to determine whether someone is currently in motion inside of your home. At its most basic, a motion detector is simply going to compare the previous status of a room to its current status. But because it does this at intervals,  it can sometimes miss things. 


  • Captures potential intruders inside of the home. 

  • Able to be wired into nearly any property. 

  • Can automatically alert you if motion is detected. 

  • Are often wireless and battery-operated. 


  • They often have the highest number of false positives. 

  • They are only on at intervals. 

  • They can be difficult to run if you have pets. 

Window Sensors 

Window sensors are designed to detect the windows being opened or broken. Contact sensors detect when the window has been opened, while  glass break sensors detect the  sound of glass breaking.  While both have fewer false alarms, they also only detect if the window is used for entry. Securing your windows is important because it prevents the intruder from ever entering your home. 

Door or window sensors are used to detect  when any door or window is opened. They can be placed in different areas of your window, depending on where they will be the most accurate. They are the most common pieces of security equipment when it comes to staying secure.  


  • Will detect if someone enters through a window with relatively high levels of accuracy. 

  • When used with other types of detection,  creates a solid security perimeter. 

  • By setting off an alarm, keeps thieves out of the home to begin with. 


  • Will not help if the individual did not have to open or break a window. 

  • Can still have false positives if there are loud sounds. 

Choosing Between Motion Detectors and Window Sensors 

Why not both? Motion detectors are best at detecting once an intruder has already entered, while window sensors are better at detecting the actual intrusion attempt. For most people, both of these things are going to be worthwhile. Motion detectors will need to be placed in specific zones of your home, while window sensors should be placed at every window. 

When you build a comprehensive security system, you often use different types of sensor and detector in different areas. Your hallways, bedrooms, and living rooms might have motion detectors installed, while your outer windows may have both contact sensors and glass break sensors installed. For the most part,  motion detectors need to be limited to the most important areas, because they can have false sensitives. Motion detectors also need to be calibrated appropriately for pets, because pets can easily set them off and (often) lead to the motion detectors not being used at all. 

If you have areas where there’s a lot of movement in general, such as rustling drapes or moving plants, a motion detector may not be usable. At the same time, a window sensor shouldn’t be relied upon for all of your security; if you leave your door unlocked, for instance, someone could simply stroll right into your home. Likewise, if someone breaks your door instead of your window, a window sensor is never going to go off. 

Want to know more about building the perfect security system? Call Brinks Home Security ™ today to get started. 

Lauren Slade is a Dallas-based writer and editor.

Share via:

We are not able to service your area yet.

Thank you...

Your request has been submitted.

One of our expert security consultants will be in touch. Together, we'll design a smart home security system to fit your lifestyle.


Interested in a Home Security System?

Complete this form and a Brinks Home™ Security Consultant will reach out regarding building your security system.

...or Call 888.627.3631

By clicking the ‘Submit’ above below, I agree that a Brinks Home specialist may contact me via text messages or phone calls to the phone number provided by me using automated technology about Brinks Home offers. This consent is not required to make a purchase. Your information is collected and used in accordance with our privacy policy. Clicking the button below constitutes your electronic signature.