What to Look for in a Home Security System: A Las Vegas Homeowner Checklist
What a top-quality Las Vegas home security system includes: door and window sensors, smart locks, motion sensors, video doorbells, and video verification.
Sting Alarm blog
How Many Contact Sensors Does Your Smart Home Security System Need?
Plan one contact sensor per exterior door and accessible window, then add sensors for safes, cabinets, and the freezer. Count yours with this guide and table.
Most homes need one contact sensor on every exterior door and one on every window that can be reached from outside, plus a few extra for things like a gun safe, medicine cabinet, or freezer. Count your doors and accessible windows, add the extras that matter to your household, and you have your number. Sting Alarm installs and monitors smart home security systems with contact sensors across Las Vegas and Phoenix.
What a contact sensor does
Contact sensors are small, simple devices with one job: they report when a door, window, cabinet, or drawer opens or closes. They are also one of the most important parts of a home security system. When the system is armed, an opened door or window starts the alarm countdown. When it is disarmed, the same sensor can send an app alert or trigger automations, so the more openings you cover, the more useful the system becomes.
How to count the sensors your home needs
Use this simple method:
- Count every exterior door, including the back door, patio and sliding doors, and the door from the garage into the house.
- Count every window that can be reached from the ground, a patio, a balcony, or a low roof.
- Add the garage door if you want to know when it opens.
- Add sensors for anything inside you want to keep tabs on, such as a safe, medicine cabinet, or game console cabinet.
- Cover large open areas and upstairs hallways with motion sensors as a second layer.
| Example home | Openings to cover | Example contact sensor count |
|---|---|---|
| Condo or apartment | 1 entry door, 1 patio slider, 2 reachable windows | 4 |
| Single-story home | 3 exterior doors, 1 garage door, 6 ground-floor windows | 10 |
| Two-story home | 3 exterior doors, 1 garage door, 6 ground-floor windows, plus 2 extras (safe, nursery door) | 12 |
These examples show the math, not a package size. Your count depends on your floor plan, and our team will walk your home to confirm it.
Ten places to put contact sensors
1. Front door
With so much activity at the front door, a contact sensor here is essential. In a break-in, it is the sensor that starts the alarm countdown. It can also tell you when kids get home, trigger a camera clip, or set back your smart thermostat. Paired with a video doorbell and a smart lock, it makes your front door the smartest one on the block.
2. Back door
A sensor on the back door lets you know when someone heads into the yard, whether it is an intruder or a child exploring while you sleep in on a weekend.
3. Door to the garage
The garage holds cars, tools, and equipment kids should not play with. A sensor on the house-to-garage door gives you instant awareness, and you can schedule alerts for weekdays only so you are not notified when you use it yourself.
4. Nursery door
If your toddler's room is upstairs, a sensor on the nursery door alerts you if they wander at night, and an automation rule can turn on the hallway light.
5. Gun safe door
Add awareness around your most dangerous possessions and get an alert if the safe is opened or left ajar.
6. Downstairs windows
A sensor on each ground-floor window lets you check from your phone that every window is closed before you leave or go to bed, and the app can remind you if you leave with one open.
7. Children's windows
A sensor on each bedroom window sends an immediate notification if a curious child opens it, and can set back the thermostat when a window is left open.
8. Video game cabinet
Want to know if homework time turned into game time? A sensor on the console cabinet can alert you when it opens or stays open too long.
9. Medicine cabinet or pillbox
A sensor can send a "no-show" reminder if the cabinet has not been opened by a set time. For an aging parent living with you, it is a respectful way to confirm medications are being taken. See our guide to home safety for families for more ideas.
10. Freezer door
Add a sensor to the freezer and get an alert if it stays open for more than a couple of minutes, before the ice cream melts.
Where else can you use one?
From screen doors to cigar humidors, Alarm.com contact sensors work almost anywhere you want to know about an opening. They connect to the Qolsys IQ Panel 5, our standard panel, which has a built-in cellular communicator and a backup battery so your sensors keep reporting during a power outage.
Plan your sensors with Sting Alarm
Not sure how many sensors your home needs? Our Las Vegas and Phoenix team will walk your home and recommend coverage for your layout. Explore smart home security or call (702) 737-8464 in Las Vegas or (602) 431-1300 in Phoenix.
Frequently asked questions
How many door and window sensors do I need?
Start with one contact sensor on every exterior door, including the door from the garage into the house, and one on every window someone could reach from the ground, a patio, or a low roof. Then add sensors anywhere you want awareness, such as a gun safe, medicine cabinet, or freezer.
Do I need a sensor on every window?
Not always. Ground-floor and easily reached windows are the priority. Upstairs windows that cannot be reached from outside can be covered by interior motion sensors, though many parents add sensors to children's bedroom windows for awareness.
What is the difference between a contact sensor and a motion sensor?
A contact sensor reports when a specific door, window, or drawer opens or closes. A motion sensor detects movement in a room or hallway. Most homes use both: contact sensors on openings and motion sensors as a second layer inside.
Can contact sensors do more than catch burglars?
Yes. With app alerts and automation rules, they can tell you when kids get home, remind you if the freezer is left open, or confirm a medication cabinet was opened on schedule.
Keep reading
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A Crime Prevention Month home security checklist for Las Vegas and Phoenix: doors, windows, lighting, landscaping, codes, smart locks, sensors, and cameras.
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