“SONOFF's Matter implementation is genuinely cross-platform — set it up once and it works everywhere.”
The SONOFF AirGuard CO2 ($45-$55) is recommended with a 8.4/10 consensus score across 7 expert reviews. Experts highlight matter-over-wifi works with apple home, google, alexa, and smartthings and ndir co2 sensor at a $50 price point — cheapest true co2 monitor. The Smart Cave says: "SONOFF's Matter implementation is genuinely cross-platform — set it up once and ..." Best for: Cross-platform smart homes, CO2 monitoring on a budget, Matter early adopters.

Affiliate link — we earn a commission at no extra cost to you
SONOFF AirGuard CO2
Sensors
SmartHomeExplorer proprietary rating
7 expert sources
The SONOFF AirGuard CO2 earns a SHE Score of 6.9/10, driven by strong value (9.9/10) with room to improve in compatibility breadth (5/10). Based on 7 expert sources and SmartHomeExplorer compatibility analysis.
How we calculate the SHE Score →Expert Consensus: 8.4/10 across 7 sources
Last verified:“SONOFF's Matter implementation is genuinely cross-platform — set it up once and it works everywhere.”
Key Features
- ✓ Matter
- ✓ NDIR CO2
- ✓ PM2.5
- ✓ Cross-Platform
- ✓ $50 Value
Best For
What Experts Agree On
What Experts Love
- ✓ Matter-over-WiFi works with Apple Home, Google, Alexa, and SmartThings
- ✓ NDIR CO2 sensor at a $50 price point — cheapest true CO2 monitor
- ✓ PM2.5 and PM10 tracking alongside CO2
- ✓ 3.6-inch display showing all readings at a glance
- ✓ No subscription required
Common Criticisms
- ✗ No radon or VOC detection
- ✗ eWeLink app less polished than competitors
- ✗ USB-C powered only, no battery option
- ✗ Matter may require firmware update for full compatibility
What The Experts Say
Ready to buy the SONOFF AirGuard CO2?
Check Price on Amazon$45-$55 · 7 expert sources · 8.4/10 consensus
Frequently Asked Questions
Is the SONOFF AirGuard CO2 worth it?
SONOFF AirGuard CO2 earns a 8.4/10 consensus score across our 12 expert sources. It is rated "Recommended" — Cross-platform smart homes. At $45-$55, SONOFF's Matter implementation is genuinely cross-platform — set it up once and it works everywhere.
Who is the SONOFF AirGuard CO2 best for?
SONOFF AirGuard CO2 is best for: Cross-platform smart homes, CO2 monitoring on a budget, Matter early adopters. Experts rate it "Recommended" overall.
How does the SONOFF AirGuard CO2 compare to other Sensors options?
Among the Sensors products we have reviewed, SONOFF AirGuard CO2 ranks above average with a 8.4/10 score. See our full category comparison for more details.
What smart home systems does the SONOFF AirGuard CO2 work with?
SONOFF AirGuard CO2 works with Amazon Alexa, Samsung SmartThings, Matter. Check our compatibility notes on the product page for any setup requirements or hub dependencies.
What are the pros and cons of the SONOFF AirGuard CO2?
The main pros of the SONOFF AirGuard CO2 are matter-over-wifi works with apple home, google, alexa, and smartthings and ndir co2 sensor at a $50 price point — cheapest true co2 monitor. The main downside is no radon or voc detection. Overall, experts rate it "Recommended" with a 8.4/10 consensus score.
Affiliate disclosure: SmartHomeExplorer.com participates in the Amazon Associates program. We earn a commission from qualifying purchases at no extra cost to you. This consensus review is based on 7 independent expert reviews — we did not test this product ourselves. Always verify current prices and availability before purchasing.

