Wireless Home Security 101 – Door and Window Sensor

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Learn more about door and window sensors

Every monitored home alarm system starts with the door/window sensor. In fact, during 20+ years in the alarm industry, I have never seen a system without one (here’s a link to designing the right system for your home). The technology goes back almost a hundred years, and over a hundred million of these devices are in use, with over a million more installed every year, just in US homes. There’s an excellent reason why this device is the core of any good alarm system: intruders invariably try to enter through a door first. Burglary entry stats look like this:

  • 34% of burglars enter through the front door
  • 26% enter through a back or basement door
  • 9% enter through the garage

That’s almost three quarters of all burglaries starting with a door – now you see why the layout of every good home alarm system starts with exterior doors (Note: don’t forget the door from the garage into the house!). The intruder wants an easy entry- and a fast and easy exit, ideally with an armload of your stuff.

How the Door/Window Sensor Works

The standard door sensor is a magnetic reed switch and consists of two small parts: one part mounts on the top of the door frame (on the opposite side from the hinge), and the smaller part (the magnet) is placed in close proximity on the door itself. When the door is shut, the two pieces are within a half inch of each other, and your alarm system can be armed. When the door opens, and the pieces are separated, that triggers the alarm. It’s simple, and it works like a charm. Most door sensors being installed today are wireless, which means no messy wiring, and the good wireless ones are smaller than your thumb. There are even wireless recessed sensors if you don’t want to see the sensors at all. Here are some more telling stats:

  • 12% of burglaries occur through an unlocked door.
  • 41% of burglaries in homes with alarm systems occur when the security system is not turned on.

So, just having an alarm system is not enough! Lock those doors and windows, and arm your system at night, as well as when you are away. Of course, with FrontPoint’s interactive, wireless home security system you can do this remotely from your iPhone – but that’s a blog topic for another day!

Comments (8)

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  1. george

    Placing a magnetic door switch/sensor at the top of the door is easily defeated. My neighbor was burglarized by someone dressed as a carpenter. He plugged into the neighbors porch outlet, used a skil saw to saw the door in-half (like a Dutch-Door) and opened the bottom half and walked right in!
    Two century old-world heirloom silver stolen from these old folks.

    • Peter M. Rogers

      George – thanks for your comment. Interesting scenario, and that is one dedicated burglar! In fact, in over twenty years in the alarm industry, this is the first time I have heard of such an innovative (and loud) way to gain entry to a home. Dressed as a carpenter – wow! That being said, as any self-respecting alarm industry professional will tell you, a correctly designed home security systems only uses the door/window sensor as the first line of defense. The interior of the home should also have motion sensors placed to cover high traffic areas that a burglar would be likely to cross in the course of searching the home. In fact, these sensors are often place to cover the front or back entry, since in many homes that is where stairs are often located, and burglars usually go upstairs to check for jewelry in bedrooms. Even if there are no stairs, front and rear doors often are located near the high traffic areas that are prime locations for motion detection. The odds of a burglar entering through a door and not going any further are almost non-existent. Sounds as if the system your neighbors had was poorly designed. This often happens when someone buys one of the less expensive “teaser” systems sold by many ADT dealers and other companies who are in it for the fast buck: they offer a very basic system for $99 to get the sale, and then when the installer shows up and tells you what you REALLY need for adequate protection, and what it costs, the homeowner decides to keep it cheap and is left unprotected. Some of these companies charge $75 to $100 per additional door, and $150 to $200 for an additional motion sensor or smoke/heat sensor. It’s highway robbery! FrontPoint charges $32.99 per additional door, and only $64.99 per motion sensor or smoke/heat sensor – and every FrontPoint system is customized based on how your home is laid out, and how the system will be used. That’s why we have such great reviews, such high customer loyalty – and how you get peace of mind. Thanks again.

  2. george

    Placing a magnetic door switch/sensor at the top of the door is easily defeated. My neighbor was burglarized by someone dressed as a carpenter. He plugged into the neighbors porch outlet, used a skil saw to saw the door in-half (like a Dutch-Door) and opened the bottom half and walked right in!
    Two century old-world heirloom silver stolen from these old folks.

    • Peter M. Rogers

      George – thanks for your comment. Interesting scenario, and that is one dedicated burglar! In fact, in over twenty years in the alarm industry, this is the first time I have heard of such an innovative (and loud) way to gain entry to a home. Dressed as a carpenter – wow! That being said, as any self-respecting alarm industry professional will tell you, a correctly designed home security systems only uses the door/window sensor as the first line of defense. The interior of the home should also have motion sensors placed to cover high traffic areas that a burglar would be likely to cross in the course of searching the home. In fact, these sensors are often place to cover the front or back entry, since in many homes that is where stairs are often located, and burglars usually go upstairs to check for jewelry in bedrooms. Even if there are no stairs, front and rear doors often are located near the high traffic areas that are prime locations for motion detection. The odds of a burglar entering through a door and not going any further are almost non-existent. Sounds as if the system your neighbors had was poorly designed. This often happens when someone buys one of the less expensive “teaser” systems sold by many ADT dealers and other companies who are in it for the fast buck: they offer a very basic system for $99 to get the sale, and then when the installer shows up and tells you what you REALLY need for adequate protection, and what it costs, the homeowner decides to keep it cheap and is left unprotected. Some of these companies charge $75 to $100 per additional door, and $150 to $200 for an additional motion sensor or smoke/heat sensor. It’s highway robbery! FrontPoint charges $32.99 per additional door, and only $64.99 per motion sensor or smoke/heat sensor – and every FrontPoint system is customized based on how your home is laid out, and how the system will be used. That’s why we have such great reviews, such high customer loyalty – and how you get peace of mind. Thanks again.

  3. Door Entry Systems

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    • Peter M. Rogers

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  4. Door Entry Systems

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    • Peter M. Rogers

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