Door Sensors and Window Sensors: Overview

Door and window sensors are the ultimate perimetral defence for your facility. Check out how they work and when to use them.

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What are Door Sensor Alarms?

Door and window sensor alarms are actually the same device. The basic functioning is a contact sensor that triggers an alarm when a door or a window is opened without authorization. This type of alarms represents the ultimate perimetral defense for your facility and it is widely used in companies and residential buildings.

Before diving into the types of alarms, let's take a look at how these sensors work.

How do Door Sensors Work?

Door and window sensors are contact sensors composed of two main parts that are a magnet and a sensor. This is also called a magnetic switch. The magnet itself is generally placed on the door while the sensor is installed on the door frame. The alarm is triggered when the door or window is opened without authorization (door-open alarm) or when the door is forced open (door-forced-open alarm).

There is a third type of alarm regarding door and windows that is triggered when the glass is broken but, as the functioning is slightly different, we have dedicated it a separate guide.

Types of Door Sensors

Door-Open Alarms

Door-open alarms activate when a door is opened by an intruder and held open for a certain period of time. The door-held-open time is programmable and used to monitor if a door is opened by an authorized access requestor. The door alarm warns the owner by emitting a chime, a loud siren sound or a flashing light, or both.

Door-open alarms are also called door-left-open alarms or door-held-open alarms. Door alarms of this type are made of two components: a magnetic stripe fixed on the door panel and an input sensor fixed at the door frame. When the contact between the magnet and the sensor is interrupted, the door alarm generates the warning signal.

Door-Forced-Open Alarms

Door-forced-open alarms activate when a door is opened by force, activating the switch contact.

An example of forced behavior is trying to get through a door without using a valid access card. Instead, the intruder uses physical force to get the door open.

All types of door alarms can be used for combination in comprehensive door alarm systems.

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How Do Door Sensors Serve Your Security Needs?

Door sensors serve to create safe homes and offices by warning against intrusion at access points that get opened often. They can work equally well with doors, windows, and cabinets.

A door-held-open alarm with a pleasant chime can warn a receptionist that a visitor has just entered the building, leaving enough room for attending other duties. When an intruder tries to forcefully break through an office door that he or she is not authorized to use, the monitoring system will let the controller know. Door-left-open alarms enable setting longer delivery times for goods and reducing them when the delivery is complete. They guard against one of the most common security intrusion events - piggybacking or tailgating.

Door alarms are effective burglary protectors. At the moment a door is opened by a burglary attempt, the sensors can activate a flashlight, a loud siren, and a phone call, or any combination of the above. The phone call system can be connected to the owner’s phone, to a private security contractor, or to a law enforcement agency.

A Look Into Wireless Door Alarms

Most advanced custom door alarms on the market use wireless technology and are therefore incredibly easy to install and use. They can be combined and integrated into a comprehensive alarm system with motion sensors, security cameras, and access control.

Since they are more sensitive and smaller than conventional alarms, wireless door alarms provide stronger, undetectable, and reliable protection for difficult-to-reach spots. They can be set independently or fit within an existing wired alarm system. Backup power supplies prevent system fallouts in event of electricity cuts.

The wireless door alarm models are usually offered in sets of several elements that can be customized with add-ons.

Do I Need a Window Sensor on Every Window?

A question that many ask is if they do need a window sensor on every window. Window sensors are meant to trigger alarms when a window is opened or forced. This means that there is no reason of installing window sensors on windows that cannot be opened or forced. Surely a window on the first floor is more likely to be used by an intruder than a window on the 5th floor.

At the end of the day, it is up to you and your team to decide on which windows the alarm should be opened. It is not necessary that all windows are covered but our suggestion would be to be protected as much as possible by enabling the alarm on all the accessible windows.

Door Sensors Manufacturers

Another important thing to consider when purchasing a door or window sensor is the brand. The options on the market are countless and the technical specs often create confusion instead of hashing out doubts.

For this reason, we have decided to briefly look through the most searched for door sensor manufacturers to help you with your choice.

Nest Door Sensors

Nest is a great place to start as it is one of the most looked for brands when it comes to security. And for a reason! Google, which owns the brand, invested in both innovation and great design making it a great security system that looks amazing.

There are really only a few downsides to this solution and it's maybe worth looking into those first. The famous critique of Nest is the price tag. These solutions can come as standalone hardware or can be purchased with a 36 months contract but these two solutions have one thing in common: they are a bit more expensive than the market average. This, however, should only concern you if you are purchasing this for your home. The price tag does not change if you are a private or a business and the solution is pretty in line if not cheaper than other commercial systems.

With regards to the pros, Nest did something that nobody had ever done before and that's merging door and window sensors with motion sensors. Basically, one single device takes care of the whole security of a room. The sensors also integrate beautifully with the rest of the Nest hardware to create a great security system overall.

As we see in our guide for the best commercial security systems, Nest is the best solution if you have a small business. Check out the guide for a better overview of the security systems landscape.

Hive Door Sensors

Hive door sensors are very different from what we've talked about so far. Their sensors are extremely customizable and can basically be set up to do whatever action. You can trigger lightbulbs turning on when a door is open or activate alerts if you're leaving your front door without having shut all the windows.

Generally, even if not extremely cheap, we see Hive as a non-business solution just because security is not the main point with Hive door sensors. The goal is more to have a smart home environment where you can be creative and customize your home however you want. Businesses, in general, tend to worry more about having a reliable security system that is easy to install and quickly grants the best security for employees and company property.

This brings us to the second criticism of Hive's sensors: the setup. The setup with these sensors tends to take a bit longer as you can really trigger any type of action you desire. Many private customers lack the necessary knowledge to install these in a short amount of time but once the solution is set up then you will surely have your ideal smart home system.

Door Sensors Ring

Ring is also a company that pops up frequently when talking about security systems. Their solution is one of the cheapest on the market and that is why it is very widespread in home security and not only commercial environments. Ring has a great variety of security solutions including some motion sensors and the door and window sensors that we will discuss now.

The door and window sensors are a great option for securing your facility without compromising your budget: the setup is easy and the solution works very well once it is installed.

In case you are a business, we would still recommend looking into other options that better integrate with cameras or access control. A great place to start the research is our guide for the best commercial security systems.

Kisi Wireless Contact Sensor

If you're looking for a complete platform that covers everything from access control to management and security, Kisi also makes wireless contact sensors.

These easy-to-install sensors attach to your door or window without any tools, and run completely wirelessly on a battery graded to last more than five years. Because they are a first-party contact sensor, they quickly connect to the Kisi access control system and begin working with your already in place Kisi products.


In conclusion, finding the best door sensors can be a bit confusing but hopefully, we have solved some doubts. If you want to know more about the best brands for door sensors, we have a more extensive guide here.

Door and Window Sensors in Access Control

Access control businesses often work with door and window sensors to grant an additional level of security. Door and window sensors can be connected to an access control system in order to use the same dashboard for both and to convert the alarm signals into notifications for the business owner or admin.

Kisi natively integrates with door and window sensors and lets you set them up from the dashboard. You can learn more about Kisi Intrusion Detection through our product page or by contacting our sales team.

If you are interested in learning more about intrusion alarms, feel free to check out our overview page.

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