Architecture
A reliable smart home should not force every function onto one protocol. Use the best physical connection for each job, preserve normal manual operation, and let Home Assistant coordinate the subsystems.
Reliability rules
- Manual wall switches should work if Home Assistant is down.
- Smoke/CO and other life-safety systems remain independently code-compliant.
- Garage and lock automation should use real state feedback, not blind commands.
- Prefer local control when practical.
- Prefer wired power/data for fixed devices when practical.
- Put the rack, network and automation core on UPS backup.
- Label and document every cable, port, zone and controller.
- Leave spare rack space, switch capacity, cable and conduit.
Installation process
1. Requirements
Inventory rooms, doors, windows, garage doors, camera views, lighting loads, HVAC zones, water-risk points, TVs, network devices, shades, audio zones, exterior areas and future plans. Decide what must work with no Internet and what must work with Home Assistant offline.
2. Site survey
Record electrical panels, alarm panels, garage-opener models, thermostat wiring, network entry, attic/basement access, construction type, existing Cat5/Cat6/security wiring and a possible rack location. Photograph every useful model label.
3. Architecture and cable plan
Choose rack, network, PoE budget, camera/NVR architecture, security sensor strategy, lighting ecosystem, garage interface, radio protocols and UPS strategy. Build a room-by-room cable schedule before pulling wire.
4. Rough-in
Pull and label cable, leave service loops, protect cable ends, test continuity, install conduit/backboxes/rack/patch panels and photograph open walls before closure.
5. Network first
Bring up router/firewall, switches, access points, VLANs if used, DHCP reservations and UPS before adding automation. A stable network avoids wasting time diagnosing automation that is really a network problem.
6. Add subsystems
A useful order is wired security → garage → lighting → cameras/NVR → locks → HVAC → water/leak protection → shades → energy → audio/media → specialty sensors.
7. Automate last
Verify device states and manual control first. Then add high-value automations such as lighting scenes, garage-open reminders, leak shutoff, person alerts, arrival/departure lighting, bedtime scene and HVAC setbacks.
Wiring
Open the dedicated, printable smart home wiring guide →
Cat6
Home-run Cat6 to exterior camera positions, video doorbells where supported, ceiling Wi-Fi APs, TVs, offices, garage, wall dashboards, attic/mechanical spaces and networked controllers. Two Cat6 runs per TV location is a useful baseline. Track both PoE port count and total PoE watt budget.
22/2 security cable
Use for simple magnetic door/window contacts and passive dry-contact sensors. Individual home runs give precise zone identity and easier troubleshooting.
22/4 security cable
Common for powered PIR motion detectors or sensors needing power plus an alarm/contact pair. Always verify the actual sensor specification.
Garage
Run network connectivity to the garage and plan the low-voltage connection to the opener/controller. Do not assume all modern openers accept a simple relay pulse; Security+ and similar buses can require a compatible interface.
HVAC, shades and audio
Run spare thermostat conductors, pathways/power to the tops of windows for future motorized shades, and in-wall speaker cable to planned audio zones. Cable is much cheaper before walls close.
Conduit
High-value conduit routes include rack-to-attic, rack-to-garage, rack-to-exterior service point, between floors and toward crawlspace/basement perimeter.
Protocols
Ethernet / PoE
Best for fixed high-bandwidth or high-reliability devices. PoE carries power and data on one cable and is ideal for cameras, APs, some doorbells, controllers and wall panels.
Zigbee
Low-power mesh for sensors, buttons, plugs, bulbs and some switches. Requires a coordinator. Mains-powered routers strengthen the mesh; battery devices generally do not.
Z-Wave / Z-Wave Long Range
Sub-GHz smart-home networking frequently used for locks, switches, relays, leak sensors, valves and motion sensors. Requires a region-appropriate Z-Wave adapter.
Matter / Thread
Matter is an interoperability layer. Thread is a low-power IP mesh transport requiring a Thread border router. Matter can also run over normal Wi-Fi/Ethernet.
Bluetooth
Useful for locks, sensors and commissioning. Bluetooth proxies can extend Home Assistant coverage.
ESPHome
Local firmware/integration commonly used for sensors, garage controllers, relays and purpose-built devices, typically over local IP.
Dry contact
A dry contact is not a network protocol; it is an isolated open/closed electrical contact. It remains one of the most useful interfaces for security contacts, float switches, garage controls and relays.
Vendor local bridge
A local bridge is not inherently bad. Systems such as Lutron can be extremely reliable when the bridge provides local operation and ordinary switches remain functional.
Subsystem design
Security
Hardwire openings and motion sensors when access is available; use Zigbee/Z-Wave for retrofits. Keep individual zones when practical.
Cameras
Prefer PoE for fixed exterior cameras. Plan field of view, night lighting, mounting, weather exposure, privacy, local storage, retention and event detection. Home Assistant feature support can differ by model.
Garage
Use a controller compatible with the opener and expose true open/closed state. Useful automations include open-too-long alerts, nighttime reminders, lights, cameras and state-confirmed closing.
Lighting
For primary lighting, favor smart wall controls rather than making normal operation depend on smart bulbs. Check neutral availability, LED/load compatibility, multi-way wiring, fan/motor ratings and local operation.
Locks
Plan mechanical fit, alignment, battery type, code management and mechanical fallback. Avoid automatic unlocking from a single weak presence signal.
HVAC
The thermostat must safely control the system without Home Assistant. Verify C-wire, heat-pump stages, dual-fuel logic, accessories and zoning before selecting a thermostat.
Water protection
Pair leak sensors at water heater, laundry, dishwasher, refrigerator, sinks, toilets, sump/mechanical areas with a tested motorized main shutoff when practical.
Energy
Whole-home and circuit-level monitoring is most useful when correlated with HVAC, appliances, EV charging and automation state.
Shades and audio
Prewire window power while walls are open. Hardwire speakers where practical and let Home Assistant coordinate scenes/announcements while native audio controls remain usable.
Documentation and maintenance
Record each device model, protocol, firmware, IP/reservation, switch port, PoE load, alarm zone, battery type, automation purpose and manual/source. Keep backups and document restore procedures. Periodically review offline devices, batteries, camera storage, UPS health, firmware and vendor/integration changes.
The private DocLookup knowledge base contains deeper architecture, wiring, protocol, subsystem and planner records so these topics can be searched alongside product model records after the Home Assistant seed is loaded.