Which system has the best looking recessed sensors?

A recessed sensor is an alarm system contact sensor that can be installed into a window or door, and which allows the system to tell if the door/window is open or closed. A recessed sensor operates in the same fashion as a surface mounted contact with the exception that the majority of the recessed unit fits into the window or door and its frame where it remains mostly hidden from view. Recessed sensors are great devices to use when the window or door trim won’t allow a sensor to be installed on top of the frame or when a homeowner prefers to hide whether a door or window is alarmed.

Even though the majority of the sensor is hidden from sight there are multiple different types of recessed sensors. Sensors come in many different makes and models. The three main attributes to check when purchasing a recessed sensor is: size, how the unit is triggered and how the unit communicates with the panel.

Let’s look at the Honeywell 951 WG. This is a 3/8" diameter miniature recessed contact with wire leads. This unit is able to fit within a 3/8" diameter hole allowing it to be installed at a window or door location where the frame has limited installation space. The magnet for the unit is the same diameter as the sensor and is only 3/4" long. This sensor activates from the magnet interacting with the reed switch within the sensor. When someone closes the door or window and the magnet rests over the reed switch, closing the circuit. When someone opens the door or window the magnet moves away from the reed switch, which then opens the circuit. The unit has 12” wire leads attached directly to the unit and will need to be spliced into the wire feed from the zone on the alarm system.

The Honeywell 956RPT is a recessed rolling plunger switch that fits into a 3/4" hole. The unit has oversized staggered set screws for easy installation of alarm wire. The unit has a mechanical rolling plunger switch that activates the switch and closes the circuit when the roller is depressed by the door or window closing. This unit is great for doors in that its rolling plunger moves with the door opening and closing. The rolling plunger allows the unit to be installed anywhere on the door frame. A regular, non-rolling, recessed plunger needs to have the plunger be pressed by the side of the door and is more suitable for sliding type doors, where the door always meets the frame head on, rather than swinging in and out.

The Honeywell 5818MNL is a wireless recessed door and window sensor. The unit activates by magnet in the same fashion as the Honeywell 951. This unit fits into a 3/4" hole but the hole will need to be at least 3” deep. Most 5800 wireless devices have a 200’ open-air, operating range. The 5818MNL may have a reduced transmission range in some cases, as the majority of the sensor will be resting within the door or window frame. This unit is perfect for wireless systems, where running a wire to the required location is not possible or is too expensive.

The only portion of the sensors listed that is exposed is the end that meets the magnet, or the plunger. The “best looking recessed sensor” is a bit of a misnomer. The question should be : what specifications will I need from a recessed sensor for my specific installation? Taking the time to research each of the sensors before purchasing will allow a user to select the right sensor for the job.