Sonoff
Sonoff SNZB-04P Zigbee Door & Window Sensor
- Zigbee2MQTT / ZHA
- Local control
- Zigbee
Prices verified September 2026
See more sensors picks on our Amazon storefront →Our verdict
The cheapest contact sensor we would actually fit to every window: smaller than the old SNZB-04, a tamper alert the Aqara P2 lacks at this price, and unobtrusive enough on a white frame that it doesn't scream 'smart home' to visitors. Sonoff rates the CR2477 coin cell at around five years, realistic if the door isn't opened dozens of times a day. Keep the sensor-to-magnet gap under 20mm when closed — go wider and it'll report false 'open' states. Pairs directly with Zigbee2MQTT or ZHA — ignore the 'Sonoff bridge required' box copy.
What can Home Assistant control on the Sonoff SNZB-04P Zigbee Door & Window Sensor?
| Control | Type | What it does |
|---|---|---|
| Contact | Binary sensor | Open/closed state of the door or window. |
| Battery | Sensor (%) | Remaining battery as a percentage. |
| Battery low | Binary sensor | Flags when the CR2032 is almost empty. |
| Tamper | Binary sensor | True when the sensor has been pried off its mount — reliable on Zigbee2MQTT, unreliable without a custom quirk on ZHA. |
| Voltage | Sensor (mV) | Raw battery voltage, more granular than the percentage figure for judging real remaining capacity. |
Zigbee2MQTT exposes contact, battery percentage, battery_low, tamper, and raw battery voltage in millivolts, but tamper support genuinely differs by integration: ZHA users report the plunger switch produces no events at all until a custom quirk is applied, whereas Zigbee2MQTT surfaces tamper correctly as its own boolean. Even under Zigbee2MQTT, clearing a triggered tamper state has been reported to throw a cluster error and leave the sensor stuck reporting tampered. Because raw voltage is published alongside the percentage, a more reliable low-battery automation trips on voltage crossing roughly 2.5V rather than trusting the coarse, non-linear percentage curve CR2032s show near end-of-life.
Specs
| size | Compact, surface-mount with adhesive |
|---|---|
| power | CR2477 (3V), ~5 years typical battery life |
| extras | Tamper alert |
| dimensions | Sensor 50.5 x 32 x 21.9mm, magnet 27 x 12 x 12.4mm, 33g total |
| sensor type | Contact (door/window) |
| detection gap | Sensor-to-magnet gap must be ≤20mm when closed |
How does the Sonoff SNZB-04P Zigbee Door & Window Sensor compare?
| Product | From | Protocol | Local control | Integration |
|---|---|---|---|---|
| Sonoff SNZB-04P Zigbee Door & Window Sensor (this product) | £11.99 | Zigbee | Yes | Zigbee2MQTT / ZHA |
| Aqara Door and Window Sensor P2 | £23.99 | Matter, Thread | Yes | Works with HA |
| Aqara Motion Sensor P1 | £18.99 | Zigbee | Yes | Zigbee2MQTT / ZHA |
| Aqara Multi-State Sensor P100 | £25.49 | Zigbee, Thread, Matter | Yes | Zigbee2MQTT / ZHA |
Frequently asked questions
- Does the Sonoff SNZB-04P Zigbee Door & Window Sensor work with Home Assistant locally?
- Yes. The Sonoff SNZB-04P Zigbee Door & Window Sensor is controlled locally in Home Assistant through Zigbee2MQTT or ZHA, so it keeps working if your internet connection or the Sonoff cloud goes down. Control and state updates stay on your own network.
- Which protocol does the Sonoff SNZB-04P Zigbee Door & Window Sensor use, and do I need a hub?
- The Sonoff SNZB-04P Zigbee Door & Window Sensor uses Zigbee. To pair it with Home Assistant you need a Zigbee coordinator (for example a SkyConnect/ZBT-1 or Sonoff dongle) attached to your Home Assistant host. Sonoff's own hub is not required when you integrate through Zigbee2MQTT or ZHA.
- How much does the Sonoff SNZB-04P Zigbee Door & Window Sensor cost in the UK?
- The lowest price we have listed for the Sonoff SNZB-04P Zigbee Door & Window Sensor is £11.99 at Amazon UK. Prices were last checked in September 2026 and change often, so confirm on the retailer's page before buying.