Build a Security System That Doesn't Charge You Monthly

ADT wants $30/month. Ring wants $10/month. SimpliSafe wants $18/month. Home Assistant wants nothing. Build a DIY alarm system with door sensors, cameras, motion detection, and instant alerts. All running locally on your network.

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Why Traditional Security Systems Are a Bad Deal

Monthly fees that never end

You buy the hardware, then pay $10-30 every month to actually use it. Cancel the subscription and your $300 system becomes a pile of plastic. Over 5 years, you'll spend $600-1,800 on subscriptions alone.

Cloud dependency

Ring had a major outage in 2024. SimpliSafe has had cloud issues. When their servers go down, your "security system" stops working. That's not security. That's a liability.

Your cameras, their servers

Ring gave police access to camera footage without warrants. Eufy was caught uploading footage despite promising local storage. Your private video belongs on your hardware, not someone else's.

Locked into one brand

SimpliSafe sensors only work with SimpliSafe. Ring cameras only get full features through Ring's app. Switch brands and you start from scratch. Home Assistant works with thousands of devices from hundreds of brands.

What a Home Assistant Security System Looks Like

Home Assistant has a built-in alarm control panel. Combined with Zigbee or Z-Wave sensors, cameras, and smart automations, you get a system that rivals the big names.

Door and window sensors

Aqara, Sonoff, and other Zigbee contact sensors cost $10-15 each and report instantly. Put them on every exterior door and ground-floor window. When a door opens while armed, Home Assistant knows immediately.

Motion detection

Zigbee motion sensors cover hallways and rooms. Combine them with camera-based person detection using Frigate for zero false alarms from pets. Know exactly when a person enters your home.

Local cameras with AI

Run Frigate NVR on your Home Assistant box for local video recording with AI object detection. Person, car, animal: your system knows the difference. No cloud upload, no subscription, no privacy concerns.

Smart alerts and sirens

Get push notifications with camera snapshots the moment something triggers. Sound a Zigbee siren. Flash your smart lights red. Send alerts to every family member. The automations are entirely up to you.

Smart locks and keypads

Arm and disarm with a PIN pad by the door, your phone, an NFC tag, or automatically based on who's home. Z-Wave locks from Schlage and Yale integrate directly. No app lock-in.

Professional monitoring (optional)

Want 24/7 dispatch? Noonlight integrates with Home Assistant for about $10/month. You get professional monitoring without giving up local control. Best of both worlds.

Home Assistant vs. Traditional Security: Real Costs

Here's what you actually spend over 3 years.

Traditional (Ring, ADT, SimpliSafe)

  • Hardware: $200-400
  • Monthly fee: $10-30/month
  • 3-year total: $560-1,480
  • Cloud dependent: Yes
  • Works offline: Limited or no
  • Camera storage: Cloud (paid)
  • Customization: Whatever they allow

Home Assistant DIY

  • Hardware: $150-350
  • Monthly fee: $0 (or ~$10 with Noonlight)
  • 3-year total: $150-710
  • Cloud dependent: No
  • Works offline: Fully
  • Camera storage: Local NVR (free)
  • Customization: Unlimited

How to Build Your Home Assistant Alarm System

1

Get a Home Assistant hub

Home Assistant Green ($99) is the easiest option. Home Assistant Yellow ($125+) if you want Zigbee built in. Or run it on a Raspberry Pi 5 ($80) or an old mini PC. Any of these work.

2

Add a Zigbee coordinator

If your hub doesn't have Zigbee built in, grab a SkyConnect USB stick ($30) or a Sonoff Zigbee dongle ($20). This lets Home Assistant talk directly to Zigbee sensors without any cloud bridge.

3

Install sensors on entry points

Put contact sensors on exterior doors and accessible windows. Aqara door sensors ($12 each) are reliable and have years of battery life. Add a motion sensor ($18) in your main hallway.

4

Set up the alarm panel

Home Assistant's built-in Alarmo integration gives you arm home, arm away, and disarm modes. Set entry delay for your front door, instant trigger for windows. Add PIN codes for each family member.

5

Configure notifications and responses

When the alarm triggers: send push notifications to phones, sound a siren, flash lights, record camera clips. Home Assistant automations let you define exactly what happens and when.

Recommended Security Starter Kit

Everything you need to get started. Total cost: roughly $200-250.

Home Assistant Green

$99. Plug and play hub. Includes Ethernet, USB ports, and enough power for a full smart home. Setup takes about 15 minutes.

SkyConnect USB Stick

$30. Adds Zigbee (and future Thread/Matter) support to your hub. Plug it in and Home Assistant detects it automatically.

4x Aqara Door Sensors

~$48 total. Cover your front door, back door, garage entry, and one ground-floor window. Battery lasts 2+ years. Tiny and discreet.

1x Aqara Motion Sensor

$18. Place in your main hallway or living area. Detects movement within seconds. Adjustable sensitivity and timeout settings in Home Assistant.

1x Zigbee Siren

$25. Heiman or Aqara siren. Triggered by Home Assistant when the alarm goes off. Loud enough to scare off intruders and alert neighbors.

Home Assistant App

Free. Get instant push notifications with camera snapshots. Arm and disarm from anywhere. View live camera feeds. Works on iOS and Android.

Frequently Asked Questions

Can Home Assistant replace a traditional alarm system?

Yes. Home Assistant supports door/window sensors, motion detectors, sirens, cameras, and smart notifications. You can build a system that matches or exceeds what ADT or Ring offers, without the monthly fee. The Alarmo integration provides a proper alarm panel with arm/disarm modes, entry delays, and per-zone configuration.

Is a Home Assistant security system reliable?

When set up with local Zigbee or Z-Wave sensors and battery backup for your hub, a Home Assistant security system is extremely reliable. It works even when your internet is down because everything runs locally. Zigbee sensors respond in under a second and have battery life measured in years, not months.

What sensors do I need for a Home Assistant alarm?

At minimum: door/window contact sensors for entry points and a motion sensor for main living areas. Add a siren, smart lock, and cameras for a more complete setup. Aqara Zigbee sensors are the most popular choice because they're affordable ($12-18 each), reliable, and have excellent Home Assistant support.

How much does a DIY Home Assistant security system cost?

A basic setup costs around $150-250: Home Assistant hub ($50-130), a few door sensors ($10-15 each), a motion sensor ($15-25), and a siren ($20-30). Compare that to Ring at $10-20/month every month, forever. The DIY system pays for itself in under a year.

Can I get professional monitoring with Home Assistant?

Yes. Noonlight integrates with Home Assistant to provide 24/7 professional monitoring and emergency dispatch for around $10/month. This gives you the best of both worlds: local control and customization with professional response when it matters.

What about camera recording?

Frigate is an open-source NVR that runs alongside Home Assistant. It provides local video recording with AI-powered object detection (person, car, animal). No cloud subscription needed. Store recordings on a local hard drive or NAS. Your video stays on your network.

Will my existing security sensors work?

Many wired security sensors (from old ADT or Honeywell panels) work with Konnected, a board that connects traditional wired sensors to Home Assistant over your local network. For wireless sensors, you'll likely need to replace them with Zigbee or Z-Wave alternatives.

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