When shopping for a smart lock, one decision quietly decides everything else: how it talks to the world.
Wi-Fi, Bluetooth, and Zigbee all promise “wireless,” yet they differ wildly in range, power draw, what happens when the Internet dies, and how much extra hardware you must buy.
1. Coverage & Range
| Protocol | Indoor Range | Extends via Mesh? | Typical Reach for a Smart Lock |
|---|---|---|---|
| Wi-Fi | ~50 m (2.4 GHz) | Only with extra mesh routers | Door to router in most homes |
| Bluetooth (BLE) | 5–15 m | Limited (BLE-Mesh exists but rare) | One room / small apartment |
| Zigbee | 10–30 m per hop | Yes, self-healing mesh | Whole house if you have ≥3 Zigbee devices |
Take-away:
- Small apartment or single door → BLE is fine.
- Multi-floor home → Zigbee mesh is the most reliable.
- Wi-Fi works if your router sits within ~15 m of the door.
2. Power Consumption & Battery Life
| Protocol | Typical Battery Life* | Why |
|---|---|---|
| Wi-Fi | 1–3 months | Radio stays on to keep TCP/IP alive |
| Bluetooth (BLE) | 6–12 months | Advertises only when needed |
| Zigbee | 8–18 months | Short, infrequent data bursts + sleep modes |
*4 × AA lithium cells, 10 unlocks/day.
Take-away:
If you hate changing batteries, Zigbee or BLE win; Wi-Fi locks are best when hard-wired or solar-assisted.
3. When the Internet Goes Down
| Protocol | Local Unlock? | Remote Unlock? | Notes |
|---|---|---|---|
| Wi-Fi | Yes | No | Lock still works on LAN, but cloud features die |
| Bluetooth | Yes | No | Phone-as-key keeps working |
| Zigbee | Yes | Depends on hub | Hub must have Ethernet backup or cellular |
Take-away:
- BLE = bulletproof local access.
- Wi-Fi locks turn “dumb” if the router reboots.
- Zigbee keeps working if your hub has failover.
4. Gateway / Hub Requirement
| Protocol | Extra Hardware Needed | Cost Impact |
|---|---|---|
| Wi-Fi | None (uses existing router) | $0 |
| Bluetooth | None (uses phone) | $0 |
| Zigbee | Zigbee hub | $25–$80 one-time |
Take-away:
- Wi-Fi and BLE are plug-and-play.
- Zigbee adds cost, but one hub supports dozens of devices—useful if you plan to expand sensors, lights, etc.
5. Security Snapshot
| Protocol | Encryption | Common Vectors |
|---|---|---|
| Wi-Fi | WPA2/WPA3 | Router misconfiguration, cloud breaches |
| Bluetooth | BLE 128-bit AES | Relay attacks if phone left unlocked |
| Zigbee | AES-128 + network key rotation | Rare; physical hub access needed |
6. Quick-Decision Matrix
| Scenario | Recommended Protocol |
|---|---|
| Renting a small apartment, want cheap & easy | Bluetooth (BLE) |
| Large house, 5+ smart-home gadgets already | Zigbee |
| Need camera + lock on same app, router nearby | Wi-Fi |
| Vacation rental, must work without Internet | BLE or Zigbee with local hub |
Bottom Line
- Convenience first → Wi-Fi.
- Battery & reliability first → Zigbee.
- Minimalism & cost first → Bluetooth.
Match the protocol to your home size, tolerance for battery swaps, and how much you fear Internet outages, and your smart lock will stay smart for years.
