🌡️ SONOFF AirGuard TH Pressure — Zigbee Temperature, Humidity & Air Pressure Sensor (SNZB-02M)

Your mini home environment monitor. The SNZB-02M is a 5-in-1 Zigbee 3.0 sensor that tracks temperature, humidity, and air pressure in real time — while the eWeLink app calculates Dew Point and VPD (Vapor Pressure Deficit) automatically. High-precision sensing with data refreshing every 5 seconds, over 2 years of battery life from a single CR2477 coin cell, and custom comfort alerts when conditions drift. It pairs with any Zigbee coordinator — SONOFF ZBBridge-P, ZBDongle-E, Amazon Echo Hub, SmartThings, or Home Assistant with ZHA / Zigbee2MQTT. Trigger fans, humidifiers, or dehumidifiers automatically based on real-time conditions. MPN: SNZB-02M.

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Free Delivery

Orders over R2,500

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Local Stock

Ships from Gauteng

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±0.2°C Accuracy

5-Second Refresh

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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

5-in-1 Monitoring — temperature, humidity, air pressure, dew point, and VPD all from one compact sensor
High-Precision Sensing — ±0.2°C temperature, ±2% RH humidity, ±0.1 hPa pressure accuracy with data refreshing every 5 seconds
Air Pressure Tracking — monitor barometric trends to anticipate weather changes; rising pressure means clearer skies, falling pressure signals rain or wind
Dew Point Monitoring — detect condensation risks early to prevent mould on walls, furniture, and valuables
VPD Analysis — essential for growers and indoor gardeners to maintain ideal transpiration conditions for healthier plants
2+ Year Battery Life — powered by a CR2477 coin cell (included); completely wireless with flexible placement anywhere including ceilings, corners, shelves, and windows
Comfort Alerts — set custom temperature, humidity, and pressure ranges; the app sends instant notifications when any reading exceeds your thresholds
Smart Automation — automatically trigger fans, humidifiers, air conditioners, or window openers based on real-time conditions via Zigbee scenes
6-Month Data History — view trend graphs for all 5 parameters with up to 6 months of free cloud storage
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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General Home Comfort

Monitor indoor comfort across rooms. Get alerts when humidity or temperature drifts outside your preferred range.

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Grow Rooms & Indoor Gardens

VPD monitoring is the grower's true compass — maintain ideal transpiration conditions for healthier plants.

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Wine Storage & Humidors

Track temperature, humidity, and pressure to maintain stable conditions for wine, cigars, and collectibles.

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Reptile & Vivarium Care

Precise environmental monitoring for terrariums where small shifts in temp, humidity, or pressure matter.

💡 What is VPD? Vapor Pressure Deficit measures the difference between how much moisture the air holds and how much it could hold. For growers, VPD is a better indicator of plant health than humidity alone — it tells you whether your plants can transpire efficiently.

💡 Why air pressure? Barometric pressure trends help predict weather changes. A steady drop (2–4 hPa in 3 hours) can signal incoming cold fronts or heavy rain. Useful for planning irrigation, protecting outdoor plants, and maintaining reptile habitats.

📡 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 Pressure
MPN / Model	SNZB-02M
Product Series	AirGuard Series
Type	Zigbee Temperature, Humidity & Air Pressure Sensor
Protocol	Zigbee 3.0 (IEEE 802.15.4)
MCU	EFR32MG22C224F512GN32
Temperature Accuracy	±0.2°C / ±0.4°F
Humidity Accuracy	±2% RH
Pressure Accuracy	±0.1 hPa
Pressure Range	700–1100 hPa
Data Refresh Rate	Every 5 seconds
Battery	CR2477 (3.0V) — included
Battery Life	2+ years (typical)
Operating Temperature	-20°C to 60°C
Operating Humidity	5–95% RH (non-condensing)
Dimensions	45 × 45 × 17.6 mm
Weight	27.3 g (including battery)
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-02M Sensor
1 x CR2477 Battery (pre-installed)
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 (Wi-Fi gateway paired with the eWeLink app), the SONOFF ZBDongle-E (USB stick for Home Assistant users), an Amazon Echo Hub / Echo 4th gen (built-in Zigbee), a SmartThings Hub, or Home Assistant with ZHA or Zigbee2MQTT. Any Zigbee 3.0 hub works — this is not proprietary to SONOFF.

Can it be used outdoors?

No. The SNZB-02M is not waterproof. It is designed for indoor use only. For outdoor temperature and humidity monitoring, consider the SONOFF SNZB-02WD which has an IP65 rating.

How do I view Dew Point and VPD?

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

What is the battery life?

Approximately 2+ years on a single CR2477 battery. To maximise battery life, ensure the sensor is within range of your Zigbee hub to minimise communication retries.

Does it work with Apple Home / Google Home?

Not directly — Zigbee devices don't join Apple Home or Google Home natively. The usual route is to run Home Assistant (with ZHA or Zigbee2MQTT) and bridge to Apple Home via HomeKit Bridge, or to Google Home via the Google Home integration. Alternatively, use 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.

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

The SNZB-02M (AirGuard TH Pressure) measures temperature, humidity, and air pressure (±0.1 hPa). The SNZB-02B (AirGuard TH Lite) measures temperature and humidity only — no pressure sensor. Both calculate dew point and VPD. Choose the SNZB-02M if you need barometric data for weather prediction, reptile habitats, or grow-room climate control.