🌡️ SONOFF AirGuard TH Lite — Zigbee Temperature & Humidity Sensor (SNZB-02B)

The invisible guardian in small spaces. The SNZB-02B is an ultra-compact Zigbee 3.0 temperature and humidity sensor with an industrial-grade Swiss Sensirion chip that refreshes data every 5 seconds. At just 27.8 mm wide, it fits into guitar cases, cigar humidors, jewellery cabinets, wine racks, and other tight spots most sensors can't reach. The eWeLink app calculates Dew Point and VPD automatically for deeper environmental insights. Powered by 2 standard AAA batteries with up to 2 years of maintenance-free operation. Pairs with any Zigbee coordinator — SONOFF ZBBridge-P, ZBDongle-E, Home Assistant with ZHA / Zigbee2MQTT. MPN: SNZB-02B.

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Free Delivery

Orders over R2,500

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Local Stock

Ships from Gauteng

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Ultra-Compact

27.8 mm Wide

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Zigbee 3.0

Requires Hub

📡 Requires a Zigbee hub. This sensor uses Zigbee 3.0 (2.4GHz mesh) — you'll need a Zigbee coordinator / hub to add it to your smart home (SONOFF ZBBridge-P, ZBDongle-E, NSPanel Pro, iHost, Amazon Echo Hub, SmartThings, or Home Assistant with ZHA / Zigbee2MQTT). Any Zigbee 3.0 hub will pair it — it's not locked to SONOFF.

⚡ Key Features

Swiss Sensirion Sensor — industrial-grade precision with ±0.2°C temperature and ±2% RH humidity accuracy; data refreshes every 5 seconds
Dew Point Monitoring — detect condensation risks early to prevent mould on walls, furniture, and valuables
VPD Analysis — Vapor Pressure Deficit monitoring for growers and indoor gardeners to maintain ideal plant transpiration
Ultra-Compact Design — only 66.3 × 27.8 × 20 mm; fits into guitar cases, humidors, jewellery boxes, wine racks, seed storage, reptile enclosures, and other tight spaces
Flexible Mounting — lanyard included for hanging, plus 3M adhesive pad for sticking; place it wherever you need monitoring
2-Year Battery Life — powered by 2 standard AAA batteries (included) for easy, tool-free replacement; no wiring, no charging
Smart Automation — set custom comfort ranges and trigger smart scenes; fans, heaters, and dehumidifiers respond automatically when conditions drift
Radiator Valve Pairing — place the sensor where you actually live, not on the radiator; it tells your smart TRV the real room temperature
6-Month Data History — view temperature, humidity, dew point, and VPD trend graphs in the app with data export support
Voice Control — works with Alexa and Google Home via eWeLink cloud-to-cloud integration
Apple Home Compatible — connect via a SONOFF Matter Bridge (ZBBridge-U or iHost) for Apple HomeKit integration
Open-Source Ready — Zigbee 3.0 for compatibility with Home Assistant (ZHA / Zigbee2MQTT) and other third-party platforms
Fully Local Control — with Home Assistant + ZHA or Zigbee2MQTT, all sensor data is 100% local — no cloud, no internet, no eWeLink account required

🏠 Perfect For

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Guitar Cases & Instruments

Monitor humidity inside cases to protect wooden instruments from cracking or warping.

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Wine Racks & Humidors

Track conditions in enclosed storage to keep wine, cigars, and collectibles at their best.

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Grow Rooms & Seed Storage

VPD monitoring plus dew point tracking for healthier plants and mould-free storage.

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Room-by-Room Comfort

Place in bedrooms, nurseries, or offices. Pair with smart TRVs for automatic heating control.

💡 AirGuard TH Lite vs AirGuard TH Pressure: The SNZB-02B (TH Lite) measures temperature and humidity. The SNZB-02M (TH Pressure) adds air pressure monitoring with ±0.1 hPa accuracy. Both calculate dew point and VPD. Choose the TH Pressure if you need barometric data for weather prediction, reptile habitats, or grow-room climate control.

📡 Don't have a Zigbee hub yet? Pair this with our SONOFF ZBBridge-P (Wi-Fi Zigbee gateway with eWeLink app) or the SONOFF ZBDongle-E (USB coordinator for Home Assistant users running ZHA or Zigbee2MQTT). Both are stocked at Eiferer.

📋 Technical Specifications

Product	SONOFF AirGuard TH Lite
MPN / Model	SNZB-02B
Product Series	AirGuard Series
Type	Zigbee Temperature & Humidity Sensor
Protocol	Zigbee 3.0 (IEEE 802.15.4)
MCU	TLSR8656
Sensor	Sensirion (Swiss industrial-grade)
Temperature Accuracy	±0.2°C / ±0.4°F
Humidity Accuracy	±2% RH
Data Refresh Rate	Every 5 seconds
Battery	2 × AAA (LR03, 1.5V) — included
Battery Life	Up to 2 years (typical)
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)
Colour	White
Casing Material	PC
Environment	Indoor use only (not waterproof)
Coordinator Required	Any Zigbee 3.0 coordinator — SONOFF ZBBridge-P, ZBDongle-E, iHost, NSPanel Pro, Amazon Echo Hub, SmartThings Hub, Home Assistant (ZHA / Zigbee2MQTT)
Works With	eWeLink (via ZBBridge) · Home Assistant · SmartThings · Amazon Alexa · Google Home · Apple Home (via Matter Bridge)
Certification	CE / FCC / RoHS
Warranty	2 Year Manufacturer Warranty

📦 What's in the Box

1 x SNZB-02B Sensor
2 x AAA Batteries (pre-installed)
1 x Lanyard
1 x 3M Adhesive Pad
1 x Quick Start Guide

❓ Frequently Asked Questions

Do I need a Zigbee hub?

Yes. Zigbee devices don't talk directly to your phone or Wi-Fi — they need a Zigbee 3.0 coordinator. Options include the SONOFF ZBBridge-P, ZBDongle-E, iHost, NSPanel Pro, Amazon Echo Hub, SmartThings Hub, or Home Assistant with ZHA / Zigbee2MQTT. Any Zigbee 3.0 hub works — this is not proprietary to SONOFF.

Can it be used outdoors?

No. The SNZB-02B is not waterproof. It is designed for indoor use only. For outdoor monitoring, consider the SONOFF SNZB-02WD (IP65 rated).

What's the difference between the SNZB-02B and SNZB-02M?

The SNZB-02B measures temperature and humidity. The SNZB-02M adds air pressure monitoring (±0.1 hPa). Both calculate dew point and VPD. The SNZB-02B is more compact and uses AAA batteries (easy tool-free swap) instead of a CR2477 coin cell.

How do I view Dew Point and VPD?

They're calculated automatically from temperature and humidity. View trend curves on the History page in the eWeLink app. If not showing, tap the gear icon in the upper-right corner to enable them.

Does it work with Apple Home / Google Home?

Not directly — Zigbee devices don't join Apple Home or Google Home natively. Use Home Assistant (with ZHA or Zigbee2MQTT) bridged to Apple Home via HomeKit Bridge, or a SONOFF Matter Bridge (ZBBridge-U or iHost) to expose Zigbee devices to Apple Home.

Does it work fully local (no cloud)?

Yes — with Home Assistant + ZHA or Zigbee2MQTT, all sensor data is 100% local. No internet, no eWeLink account, no cloud dependency.