Sonoff Air Guard Series E-Ink – Humidity and temperature sensor with E-Ink display, Zigbee, white (SNZB-02UL)

The SONOFF AirGuard SNZB-02UL is a Zigbee temperature and humidity sensor with a 2.9-inch E-Ink display, designed for measuring and displaying indoor environmental data. Its built-in Sensirion sensor provides an accuracy of ±0.2 °C for temperature and ±2% for relative humidity, with measured values refreshed every 5 seconds. The E-Ink display remains easy to read from an almost 180° viewing angle and even in strong ambient light.

The sensor can also be used without a Zigbee connection: it displays the current temperature and humidity, and the last 6 hours of measurement history can be reviewed directly on the device. With a compatible Zigbee gateway or Home Assistant system, the display can also show the time, date, weather information, comfort status, and temperature and humidity data from another sensor.

When connected to a Zigbee network, the SNZB-02UL can be used with eWeLink, Home Assistant, Zigbee2MQTT, ZHA, SmartThings and selected Amazon Alexa systems. eWeLink supports up to 6 months of temperature, humidity, dew point and VPD history, CSV export, threshold alerts and automation conditions. The sensor can also be used as an external temperature source for compatible SONOFF thermostatic radiator valves.

About SONOFF

SONOFF manufactures smart home devices, relay modules, energy meters, wall switches, Zigbee sensors, control panels, gateways and various electrical installation accessories. Its product range includes devices using Wi-Fi, Zigbee, Matter and LAN communication.

SONOFF devices are primarily based on the eWeLink platform, but many products can also be integrated with Home Assistant, Zigbee2MQTT, ZHA, SmartThings, Alexa, Google Home and other smart home systems. In addition to residential smart home solutions, the manufacturer's range includes DIN rail-mounted devices, energy monitoring solutions and products suitable for professional installation.

Key product features

• 2.9-inch E-Ink display: Anti-glare, paper-like display with an almost 180° viewing angle. It remains easy to read even in direct, strong ambient light.
• Multiple data points on one screen: When paired and connected to a network, the display can show temperature, humidity, time, date, weather information and comfort status at the same time.
• 6-hour data review: Using the button on the device, temperature and humidity data from the previous 6 hours can be reviewed directly on the display, even without a Zigbee gateway.
• Remote temperature and humidity display: If the SNZB-02UL and another compatible SONOFF sensor are connected to the same gateway, values measured by the other sensor can also be displayed on the SNZB-02UL screen.
• Alerts and automations: Custom temperature and humidity thresholds can be configured. Exceeding a threshold can trigger a notification or smart home automation, such as switching on a fan or humidifier.
• Four mounting options: The device can be placed on a table using the built-in stand, attached to a metal surface magnetically, hung on a wall, or installed using the included adhesive mounting option.

Smart home protocols and platform compatibility

• Zigbee: Uses Zigbee communication based on IEEE 802.15.4. A compatible Zigbee gateway is required for online functions.
• eWeLink: With a SONOFF Zigbee gateway, device control, measurement history, alerts and automations are available.
• SONOFF gateways: ZBBridge-P, ZBBridge-U, Bridge-M and NSPanel Pro are supported; iHost compatibility depends on the firmware version.
• Home Assistant: Can be integrated using ZHA and Zigbee2MQTT. Some display functions require SONOFF configuration files or a Blueprint.
• SmartThings: Can be used with SmartThings Hub V3 and Aeotec Smart Home Hub V3.
• Amazon Alexa: Can connect directly to compatible Echo devices with a built-in Zigbee hub, or can be used through eWeLink integration.
• Google Home: Can be used through eWeLink cloud integration.
• Apple Home and Matter platforms: Can be integrated through a compatible SONOFF Matter Bridge.

Smart features

• Temperature measurement: ±0.2 °C accuracy with a 5-second display refresh interval.
• Humidity measurement: ±2% RH accuracy.
• Measurement history: 6 hours of local history on the display, a 24-hour graph and up to 6 months of data storage in eWeLink.
• Data export: Measurement history can be exported in CSV format.
• Dew point and VPD: eWeLink calculates dew point and VPD values from the measured data.
• Calibration: Temperature and humidity measurements can be adjusted separately.
• Comfort ranges: Six configurable temperature and humidity profiles can be set.
• Alerts: Notifications can be assigned to configured temperature and humidity thresholds.
• Automations: Temperature, humidity and offline status can be used as automation conditions, with an optional delay.
• Remote sensor display: Temperature and humidity data from a compatible SONOFF sensor can also be shown on the display.
• Compatible sensors: SNZB-02P, SNZB-02D, SNZB-02WD, SNZB-02LD, SNZB-02DR2, SNZB-02B, SNZB-02M and SNZB-02UL.
• TRV temperature source: Can be used as an external temperature sensor for a compatible SONOFF thermostatic radiator valve.
• Time, date and weather: With a compatible gateway or Home Assistant configuration, these data can also be shown on the display.
• Reporting settings: The reporting threshold and data reporting interval can be adjusted.
• Sharing: The device can be shared with other eWeLink accounts.
• OTA update: Firmware updates are supported through a compatible SONOFF gateway, ZHA or Zigbee2MQTT.

Power supply

• Power supply: 3.0 V DC using 2 × 1.5 V AAA/LR03 batteries.
• Battery type: LR03 AAA.
• Battery life with Zigbee connection: At least 8 months according to manufacturer laboratory data.
• Battery life in standalone use: At least 15 months without a Zigbee gateway according to manufacturer laboratory data.
• Battery consumption: With a Zigbee connection, time synchronisation, data communication and updating network-supplied display information increase power consumption. Actual battery life depends on configuration and usage.
• Battery status: With a compatible gateway and platform, the current battery level can also be checked remotely.

Technical specifications

• Product series: SONOFF AirGuard Series
• Product type: Zigbee temperature and humidity sensor
• Model: SNZB-02UL
• MCU: TLSR8258
• Sensor: Sensirion temperature and humidity sensor
• Power supply: 3.0 V DC, 2 × 1.5 V
• Battery: 2 × LR03 AAA
• Display type: E-Ink
• Display size: 2.9 inches
• Viewing angle: Nearly 180°
• Wireless connection: Zigbee, IEEE 802.15.4
• Dimensions: 99.1 × 51.1 × 18.6 mm
• Colour: White
• Housing material: PC
• Usage environment: Indoor
• Operating temperature: 0–50 °C
• Operating humidity: 5–95% RH, non-condensing
• Temperature measurement accuracy: ±0.2 °C
• Humidity measurement accuracy: ±2% RH
• Measurement data refresh: Every 5 seconds
• Certifications: CE, FCC, RoHS