Home Assistant Security System: Privacy-First Protection for NZ Homes
A Home Assistant security system puts you in complete control of your smart home data — no cloud servers, no third-party access, and no subscriptions. For NZ homeowners who value privacy alongside security, Home Assistant offers a unique proposition: an open-source smart home platform that runs entirely on local hardware in your home, keeping every camera feed, sensor reading, and automation rule on your own network. In an era where every smart home device wants to phone home to a distant server, Home Assistant takes the opposite approach.
This guide walks through building a locally controlled security system using Home Assistant, covering hardware requirements, sensor integration, camera management, and the Alarmo alarm panel — all without sending a single byte of your data to the cloud.
Why Privacy Matters for Home Security
Most commercial smart home security systems rely on cloud infrastructure. When your Ring camera detects motion, the footage travels to Amazon’s servers. When your Google Nest alarm triggers, the event data goes to Google. When your Eufy doorbell records a visitor, the clip may be stored on Eufy’s servers. You are trusting these companies to store your most intimate data — footage of your family, your daily routines, your comings and goings — securely and responsibly.
High-profile incidents have shaken that trust. Cloud security breaches, employees accessing customer footage, data-sharing partnerships with law enforcement, and companies changing their privacy policies retroactively have all made headlines. For privacy-conscious NZ homeowners, these incidents raise a fundamental question: why should your home security data leave your home at all?
Home Assistant answers that question by keeping everything local. Camera footage stays on your hard drive. Sensor data stays in your database. Automation rules execute on your hardware. The system works without an internet connection, and no external entity — not even the Home Assistant organisation — has access to your data.
- All data processed and stored locally on your own hardware
- No cloud servers, no external data storage, no third-party access
- System continues to function during internet outages
- No subscriptions or ongoing fees for any functionality
- Open-source code means the software can be audited by anyone
Hardware: What You Need to Run Home Assistant
Home Assistant runs on a variety of hardware, from dedicated devices to repurposed old computers. For a security-focused installation, choosing the right hardware ensures reliable performance and adequate storage for camera recordings.
The Home Assistant Green is a purpose-built device priced at approximately $150 NZD. It provides a plug-and-play experience with pre-installed software, adequate processing power for a moderate smart home, and a compact form factor. For basic security setups with a few cameras and up to 30 sensors, it handles the workload comfortably.
The Home Assistant Yellow offers more powerful hardware with a built-in Zigbee radio, eliminating the need for a separate USB coordinator. It is based on a Compute Module 4 and supports NVMe storage for fast, reliable camera recording. At approximately $200-250 NZD (depending on specification), it is the premium option for security-heavy installations.
For the most cost-effective approach, a Raspberry Pi 5 with an SSD (approximately $120-150 NZD total) runs Home Assistant well and provides sufficient performance for most residential security setups. Pair it with a SONOFF Zigbee 3.0 USB Dongle Plus ($30-40 NZD) for Zigbee sensor support.
Storage is the critical consideration for security installations. If you are recording camera footage locally, you will need adequate storage capacity. A 1 TB SSD provides approximately 30 days of continuous recording from two cameras at moderate quality, or significantly longer with motion-triggered recording. Avoid SD cards for camera storage — their limited write endurance makes them unreliable for continuous recording.
Integrating Security Sensors with Home Assistant
Home Assistant supports virtually every smart home sensor on the market through its extensive integration library. For a security system, you need door and window contact sensors, motion sensors, and optionally glass break detectors and vibration sensors.
Zigbee sensors are the most popular choice for Home Assistant security installations. Using a USB Zigbee coordinator (like the SONOFF Zigbee 3.0 dongle) and the ZHA (Zigbee Home Automation) or Zigbee2MQTT integration, you can connect Aqara, IKEA, Sonoff, and dozens of other Zigbee sensor brands directly to Home Assistant without any cloud dependency.
Z-Wave sensors connect through a USB Z-Wave controller (like the Aeotec Z-Stick 7) and the Z-Wave JS integration. For security-critical sensors, Z-Wave’s mandatory encryption provides an additional layer of confidence that sensor communications cannot be intercepted or spoofed.
The sensor setup process in Home Assistant involves pairing each device with the Zigbee or Z-Wave network, assigning it to a room, and naming it descriptively (e.g., “Back Door Contact” or “Hallway Motion”). Once paired, the sensor’s state is immediately available for automations and dashboard display.
Home Assistant’s ZHA integration supports over 2,500 Zigbee devices from hundreds of manufacturers. If a sensor communicates via Zigbee, there is an extremely high probability that it works with Home Assistant out of the box.
Alarmo: A Full-Featured Alarm Panel for Home Assistant
Alarmo is a custom integration for Home Assistant that transforms your sensor network into a fully featured alarm system. It provides arming modes (away, home, night, custom), entry and exit delays, sensor grouping, notification actions, and siren control — all configured through an intuitive graphical interface.
Setting up Alarmo involves selecting which sensors are monitored in each arming mode. In “away” mode, all sensors are active. In “home” mode, you might disable motion sensors (to allow movement inside) while keeping door and window sensors active. In “night” mode, you might enable all perimeter sensors plus hallway motion sensors while excluding bedroom areas.
When an alarm condition is triggered, Alarmo can execute a sequence of actions: sound a siren (either a dedicated smart siren or through smart speakers), send notifications to your phone via the Home Assistant companion app, flash smart lights red, lock all smart locks, and begin recording on all cameras. The response is fully customisable and executes entirely locally.
Alarmo also supports multiple user codes, allowing each household member their own PIN for arming and disarming. It logs all events with timestamps, creating a comprehensive security audit trail accessible through the Home Assistant dashboard.
Camera Integration: Local Recording and AI Detection
Home Assistant integrates with IP cameras from virtually every manufacturer, displaying live feeds on dashboards and recording footage to local storage. For a privacy-first security system, all camera footage stays on your local network and is never uploaded to external servers.
The Frigate integration adds AI-powered object detection to your cameras, running a local AI model that can distinguish between people, cars, animals, and other objects. Frigate processes video locally using your hardware’s CPU or a dedicated AI accelerator (like a Google Coral USB), providing intelligent alerts without any cloud AI service.
With Frigate configured, your cameras only record and alert when a person is detected — dramatically reducing false alarms from animals, shadows, and swaying vegetation. The system can send you a notification with a snapshot of the detected person, allowing you to assess the situation instantly from your phone.
For NZ homeowners, the combination of Home Assistant, Alarmo, and Frigate creates a security system that matches or exceeds commercial offerings in capability while keeping all data completely private and under your control.
Getting Started: A Practical Roadmap
Building a Home Assistant security system is a project that rewards a methodical approach. Here is a practical roadmap for NZ homeowners ready to take the plunge.
Phase 1 involves setting up Home Assistant on your chosen hardware, connecting it to your home network, and installing the companion app on your phone. This establishes the foundation and familiarises you with the platform’s interface and concepts.
Phase 2 adds Zigbee sensors. Install a USB coordinator, pair your door and window sensors, and create basic automations — such as sending a notification when a door opens. This gives you immediate practical value while building your confidence with the platform.
Phase 3 deploys Alarmo. Configure your arming modes, assign sensors to each mode, set up entry and exit delays, and test the system thoroughly. At this point, you have a functional alarm system that rivals commercial alternatives.
Phase 4 integrates cameras with Frigate for AI-powered detection and local recording. This is the most technically demanding phase but delivers the most significant capability uplift.
Each phase can be completed independently, and the system is useful at every stage. You do not need to complete all four phases to benefit from Home Assistant — even a basic sensor and notification setup provides genuine security value with complete privacy. The beauty of the platform is that it grows with you, at your pace, under your control, and entirely on your terms.
