What Home Assistant Actually Is (and Is Not)

Home Assistant is free, open-source software that runs on a small computer in your house and connects to basically every smart home device that exists. For security purposes, it can monitor door sensors, window sensors, motion detectors, and cameras, then send you alerts and trigger automations based on rules you set.

What it is not: a professional monitoring service. Nobody is watching your house. There is no dispatch center. It is a self-monitoring platform, and a very powerful one if you are willing to set it up properly.

What You Need to Get Started

The hardware list is shorter than most people expect.

  • A Home Assistant device: Raspberry Pi 4 ($55) or a Home Assistant Green ($99) or an old mini PC
  • A Zigbee coordinator: Sonoff Zigbee 3.0 USB Dongle Plus ($25) or SkyConnect ($30)
  • Door/window sensors: Aqara door sensors ($13 each) or Sonoff SNZB-04 ($9 each)
  • Motion sensors: Aqara motion sensor ($20) or IKEA Vallhorn ($10)
  • Optional: Zigbee siren like the Heiman HS2WD for audible alerts ($25)

Setting Up the Basics

Install Home Assistant on your device. The official installer handles most of this. Plug in the Zigbee coordinator. Install the Zigbee Home Automation (ZHA) integration or Zigbee2MQTT if you want more control.

Pair your sensors. Put them in pairing mode, let Home Assistant discover them, and name them something obvious. Front Door, Back Door, Kitchen Window. Not Sensor 1, Sensor 2. You will thank yourself later when an alert fires at 2 AM.

Building Security Automations

The real power is in automations. Here is what a basic security setup looks like.

  • When any door sensor opens and the alarm is armed, send a push notification to your phone immediately
  • When motion is detected in the hallway after midnight, turn on a siren and send a camera snapshot
  • When nobody is home (phone GPS leaves a zone), automatically arm all sensors
  • When you arrive home, disarm and send a welcome notification (or just turn on the porch light)

Adding Cameras via RTSP

Most decent security cameras support RTSP streaming. Reolink, Amcrest, eufy (with some workarounds), and Hikvision all work. Add the camera as a generic RTSP feed in Home Assistant and you get live view plus the ability to capture snapshots for automations.

For recording, Frigate is the go-to add-on. It handles motion detection with AI-based person and object recognition, records only when something interesting happens, and stores clips locally. It runs on a Coral TPU ($25 to $35) for fast detection, or on your CPU if you only have a couple cameras.

What Home Assistant Replaces (and What It Does Not)

It replaces: a basic alarm panel, notification apps, most cloud-based sensor monitoring, and the need for brand-specific hubs for many Zigbee and Z-Wave devices.

It does not replace: professional monitoring dispatch, cellular backup for internet outages (though you can add that), or the simplicity of a plug-and-play system like SimpliSafe or Ring.

If you enjoy tinkering even a little bit, the trade-off is worth it. If you want something your whole family can use without any learning curve, a dedicated alarm system is still the easier path.

My Recommended Starting Order

  • Week 1: Install Home Assistant, set up Zigbee, add 2 to 3 door sensors, configure phone notifications
  • Week 2: Add motion sensors, build your first automation for armed/disarmed states
  • Week 3: Add cameras via RTSP, set up live view in the dashboard
  • Week 4: Install Frigate for smart recording, add a Zigbee siren if you want audible alerts
  • After that: Tune notification rules, add more sensors as needed, and build the dashboard your household will actually use