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Quick verdict
A dead-simple Zigbee contact sensor at a price that lets you put one on every door and window in the house. The P version brings improved range and battery over the original. Pair with a Zigbee coordinator, add to Home Assistant, and automate away - lights on when the front door opens, alerts when the garage is left open, that kind of thing.
Standout: One of the cheapest Zigbee contact sensors on the market, making it practical to cover every door and window.
Notes last checked Mar 23, 2026.
Compatibility snapshot
Home AssistantexcellentFull local control, no cloud needed. Native Home Assistant integration or a local protocol.
Apple HomenoneNo official support on this platform.
Google HomenoneNo official support on this platform.
AlexanoneNo official support on this platform.
Works offlineyes
Setupeasy
Extra hub neededyes
Powerbattery
Local control facts
Home Assistant: zha integration, Local Polling (home-assistant.io, checked Oct 10, 2026)
Zigbee2MQTT: supported device, listed as SONOFF SNZB-04P (Contact sensor) (zigbee2mqtt.io, checked Oct 10, 2026)
Why it stands out
among the cheapest Zigbee contact sensors you can find
compact enough to fit on most doors and windows without standing out
improved battery life and Zigbee range over the older SNZB-04
Reasons to hesitate
requires a Zigbee coordinator - no standalone use
no built-in temperature sensor (some competitors include one)
no native voice assistant support without Home Assistant bridging
Best for
Home Assistant users who want to monitor every door and window cheaply
triggering automations when doors open - lights, alerts, HVAC adjustments
Avoid if
you do not have a Zigbee coordinator
you want a contact sensor that works directly with Alexa or Google Home
Privacy and local-control notes
Pure Zigbee device with no cloud component. Fully local when paired with a Zigbee coordinator.
Home Assistant support: supported · integration path: zigbee2mqtt / ZHA.
Buying reality check
Price notes: Rock-bottom pricing for a Zigbee contact sensor. The P version replaces the original SNZB-04 with better range and battery life.
SONOFF's second-generation Zigbee radiator valve is smaller, costs more, and is supported in Zigbee2MQTT. A stopgap ZHA quirk shipped in zha-quirks 2.4.0.
From the change log and the news briefs that name this product.
Verified against
The compatibility notes above have not been through the source audit yet.
The manufacturer's page is here; the notes were last checked Mar 23, 2026.
SONOFF TRV Gen2 (TRV-ZBT) in Home Assistant: setup, calibration and ZHA vs Zigbee2MQTT
The SONOFF TRV Gen2 (TRV-ZBT) is well supported in Zigbee2MQTT 2.12.1+, and zha-quirks 2.4.0 added a basic ZHA quirk. Pairing, calibration, room sensors.
