SONOFF AirGuard CO₂ SAWF-08P

A better glance at one part of the room

SONOFF AirGuard CO₂ puts carbon dioxide in large digits, with temperature and humidity visible underneath. That is its strongest feature. You can watch the CO₂ reading during a long home-office session without opening an app or cycling through several display modes.

The single SAWF-08P was listed at $49.90 in SONOFF's US store on September 9, 2026, with tax marked included and shipping extra. At that price, it needs a reason beyond simply measuring room conditions. The screen, configurable sound and light alerts, and direct Wi-Fi connection provide that reason for a buyer who wants the information on the desk.

It does not measure particles. The similarly shaped AirGuard PM2.5/PM10 is a different sensor, not a cheaper version with the same measurements. Choose this CO₂ model when carbon dioxide is the information you want; choose the particle model when tracking airborne particles is the job.

The screen is useful; the cable is less convenient

AirGuard uses an NDIR CO₂ sensor, with a manufacturer-specified five-second update interval. That is frequent enough to make a changing number the focus of the product, but it is not evidence of independently tested accuracy or a faster response than competing sensors.

The 70 × 103 × 26 mm case has a desktop stand. It needs continuous 5 V USB-C power, so it cannot live wherever you happen to place a battery sensor. SONOFF also advises against mounting it flat against a wall because the rear vents need clear airflow.

For a desk near a power source, those compromises are manageable. For a neat, cable-free wall display, this is the wrong form factor. The buzzer and colored indicator can draw attention to readings, while eWeLink's quiet hours let you suppress those alerts when they would be unwelcome.

A useful record, with an app attached

eWeLink offers up to a year of CO₂, temperature and humidity history, with export. That can help compare the room across days rather than relying on one glance. Those vendor charts and alert settings do not automatically transfer into a Matter app.

SONOFF now explicitly lists the three numeric readings in Home Assistant, SmartThings, Google Home and Apple Home; its Apple humidity note requires iOS 26 or later. Alexa is the weaker option, receiving an air-quality level and temperature rather than numeric CO₂ or humidity. The monitor's own screen is therefore a stronger reason to buy than an expectation that every voice assistant will report everything.

IKEA makes the value decision harder

IKEA ALPSTUGA is listed at $34.99 and measures CO₂, PM2.5, temperature and humidity. It shows one selected reading at a time, needs separately purchased USB power accessories, and uses Thread for connected readings.

If you already have a Thread border router and want broader room monitoring, we would favor ALPSTUGA's feature set. Choose AirGuard CO₂ when its simultaneous display, alerts, Wi-Fi or eWeLink history will be more useful to you than the extra particle sensor.