Where Should I Install the Alarm Sensor On My Sliding Door?

The place where you should install the alarm sensor on your sliding door is either at the top of the door or the side of the door. If the door opens from both sides, then you will need two (2) door and window sensors to truly compete the setup. Slimline sensors are often used for this job.

With any door sensor, regardless of where it is installed, the same general principle applies. The larger sensor is placed on the door frame, while the smaller magnet is placed on the moving portion of the door. The reason for this is that the sensor is less likely to be damaged on the stationary frame than on the moving door. The sensor and magnet should be as close as possible (usually within a half inch) when the door is closed. Ideally, they should be in direct contact. That is how door and window sensors get their popular nickname of "contact" sensors. Make sure the sensor and magnet are properly aligned according to any indication marked on the sensor.

When the door is slid open, the magnet on the door will slide away from the sensor. This will release the metal reed switch inside the sensor. The sensor will then know to alert the system regarding the open door. Then when you close the door, the magnet will return to its original position, and the reed switch inside the sensor will close. For a sliding door that opens on both sides, you will need two (2) sensors in total. You will position the sensors on separate sides of the door so that alerts are triggered regardless of which side of the door is opened.

The most common locations for a door sensor installed on a sliding door are at the top of the door and at the side of the door. Really, it does not matter too much. What is important is that the sensor and magnet are close enough when the sliding door is closed and that the magnet properly separates when the door is opened. It is strongly recommended that you test your door sensor after installing so that you are sure that it functions in the manner that you want.