Sonoff AirGuard TH Lite – Zigbee Temperature and Humidity Sensor (SNZB-02B)

Product detailed description

🌡️ SONOFF AirGuard TH Lite (SNZB-02B) – Smart Guardian of Your Ideal Climate

Sonoff AirGuard TH Lite (SNZB-02B) is a battery-powered Zigbee 3.0 sensor for measuring ambient temperature and relative humidity. From the measured values, it automatically calculates the dew point and Vapor Pressure Deficit (VPD) for a detailed overview of your environment. Detect condensation risks in time, prevent mold growth on walls, furniture, or valuables, and maintain ideal conditions for plant transpiration and healthier growth. Equipped with an industrial-grade Swiss Sensirion sensor, it guarantees high measuring accuracy. It measures temperature with an accuracy of ±0.2 °C (±0.4 °F) and humidity with ±2% RH. Data updates every 5 seconds for reliable real-time monitoring.

Thanks to its compact dimensions of just 27.8 mm in width and 20 mm in thickness, you can easily place it in tight spaces. It offers flexible installation via hanging or adhesive mounting – ideal for guitar cases, cigar humidors, jewelry boxes, wine cellars, or other compact locations.

The device is powered by two standard AAA batteries, which are easy to replace without any tools. They ensure up to 2 years of maintenance-free operation (based on internal laboratory tests; actual battery life may vary depending on environmental conditions and settings).

This sensor goes beyond standard temperature and humidity measurements. Thanks to dew point calculation, it can alert you in advance to the risk of water condensation on surfaces, which leads to mold growth. If surface temperature drops below the dew point, forming moisture creates an ideal environment for mold – with this sensor, you can catch the threat before it appears.

Equally important is the VPD (Vapor Pressure Deficit) monitoring feature, highly valued by greenhouse and indoor growers. VPD offers a much more accurate view of the balance between temperature and humidity than humidity alone. Instead of guessing, you get precise data to effectively control ventilation, optimize growing conditions, and set automations for healthy plant development.

In the eWeLink app, simply choose your custom target ranges for temperature and humidity. System alerts notify you instantly if values exceed your thresholds, making it easy to prevent overheating, overly dry air, or excessive humidity.

Through smart scenes, the SONOFF SNZB-02B AirGuard TH Lite can automatically control other smart home devices. When humidity is high, it triggers a dehumidifier or ventilation; in dry conditions, it activates a humidifier; and in heat, it turns on the AC. It serves as your companion for automated comfort, reduced energy consumption, and home protection.

Enjoy 6 months of free cloud storage to track temperature and humidity trends anytime. With data export options, every analysis you make will be backed by accurate historical data.

Once paired with the eWeLink app and connected via Cloud-to-Cloud integration, you can check climate data using voice commands. Thanks to compatibility with Alexa and Google Home, a simple voice command lets you check current temperature or humidity without opening the app.

The device uses the Zigbee 3.0 standard and is compatible with SONOFF Zigbee gateways, as well as many other Zigbee 3.0 systems including Home Assistant (ZHA, Zigbee2MQTT), SmartThings, and Amazon Alexa Zigbee Hub.

Comparison of SNZB-02B and SNZB-02P

Key Features

🌡️ Temperature Measurement: Indoor temperature monitoring with ±0.2 °C accuracy

💧 Humidity Measurement: Relative humidity measurement with ±2% RH accuracy

💦 Dew Point Calculation: Calculates and displays dew point based on measured temperature and humidity

🌱 VPD Calculation: Displays Vapor Pressure Deficit value for plant growth and climate optimization

🔔 Alerts: Notifications when measured values leave the configured comfort range

⏱️ Fast Data Updates: Measured data refreshes as fast as every 5 seconds

📶 Zigbee 3.0 Communication: Low-power wireless communication compatible with Zigbee gateways

🔋 Battery Powered: Powered by 2× LR03 AAA batteries

📊 Data Logging: Temperature, humidity, dew point, and VPD history available in the eWeLink app

📈 7-day, monthly, and 6-month trend history

📁 CSV Export: Option to export historical measurement data to CSV format

Protocols and Compatibility

📶 Zigbee 3.0: IEEE 802.15.4 wireless communication

📱 eWeLink: Full functionality when used with a SONOFF Zigbee Gateway

Compatible SONOFF Gateways: ZBBridge-P, ZBBridge-U, NSPanel Pro, iHost, and supported SONOFF Zigbee USB coordinators

🏠 Home Assistant: Integration supported via ZHA or Zigbee2MQTT

⚙️ SmartThings: Compatible with Aeotec SmartThings Hub V3

🗣️ Amazon Alexa: Compatible with Echo devices featuring a built-in Zigbee hub

🌐 Google Home: Temperature and humidity data accessible via eWeLink Cloud integration

🔄 MQTT: Native MQTT is not supported, but automation is possible via Zigbee2MQTT

🔌 Local / Offline Operation: Works without internet access when used with a local system (e.g. Home Assistant with ZHA / Zigbee2MQTT)

☁️ Cloud Operation: Remote access available via eWeLink, SmartThings, or other supported cloud platforms

Specifications

🏷️ Product Name: SONOFF AirGuard TH Lite

🆔 Model: SNZB-02B

🏷️ Product Type: Zigbee Temperature and Humidity Sensor

🧠 MCU: TLSR8656

⚡ Power Supply: 3.0 V (2× 1.5 V batteries)

🔋 Battery Type: 2× LR03 AAA

⏳ Estimated Battery Life: Approximately 2 years

📶 Wireless Connection: Zigbee 3.0, IEEE 802.15.4

📊 Measured Values: Temperature, Relative Humidity, Dew Point, VPD

🌡️ Temperature Accuracy: ±0.2 °C / ±0.4 °F

💧 Humidity Accuracy: ±2% RH (relative humidity)

❄️ Operating Temperature: -20 °C to +60 °C

💦 Operating Humidity: 5 – 95% RH (non-condensing)

📐 Dimensions: 66.3 × 27.8 × 20 mm

⚖️ Weight: 43 g (including batteries)

🛡️ Housing Material: PC (Polycarbonate)

🎨 Color: White

🏠 Installation Environment: Indoor

📜 Certifications: CE, FCC, RoHS