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 might not want to lean to some options in different areas. Here’s everything you need to know about motion detector and window sensor pros and cons.

Motion Detectors

Motion detectors use a number of 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.

Positives of a motion detector include:

  • Captures potential intruders inside of the home.
  • Able to be wired into nearly any property.
  • Can automatically alert you if motion is detected.

Negatives of a motion detector include:

  • They often have the highest number of false positives.
  • They are only on at intervals.
  • They’re difficult to run if you have pets.

Window Sensors

Window sensors are designed to detect the windows being open or broken. Contact sensors detect when the window has been opened, while glass breaking sensors actually detect the sound of glass breaking. Both of these have fewer false alarms, but 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 can be placed in different areas of your window in order to be the most accurate. They are the most common piece of security equipment when it comes to securing your home. Door or window sensors are used to detect when any door or window is opened.

Positives of a window sensor include:

  • 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.

Negatives of a window sensor include:

  • 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 breaking 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 it 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? It’s not hard: all you have to do is pick up the phone! Contact Protect America today to get started.