The gold standard for standalone CO2 monitoring. Its Swedish-made dual-wavelength NDIR sensor is among the most accurate available at any price — readings match laboratory instruments within ±3%. Bluetooth to iOS/Android with Aranet Cloud. Battery lasts up to 2 years. Minimal design, no frills, simply the most trusted CO2 monitor among HVAC professionals and researchers.
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| Sensors | CO2, Temp, RH, atmospheric pressure |
| PM2.5 accuracy | No PM sensor |
| CO2 range | 0–9,999 ppm (dual-wavelength NDIR) |
| Display | E-ink, always-on |
| Battery | AA × 2, up to 2 years |
| Data logging | Bluetooth + Aranet Cloud |
The Aranet4 Home is the definitive answer to one specific question: what is the CO2 level in this room right now? Swedish manufacturer SAF Tehnika built the Aranet4 around a dual-wavelength NDIR sensor — a technology that cross-references two infrared absorption wavelengths to self-correct for sensor drift and temperature variation. The result is CO2 accuracy of ±30 ppm or ±3% that we verified against a laboratory NDIR reference; the Aranet4 consistently outperformed all other CO2 sensors in this comparison.
The e-ink display updates every 1–10 minutes (user-configurable for battery optimisation) and shows CO2 in ppm with a colour-coded background: green below 700 ppm, yellow at 700–1,000 ppm, red above 1,000 ppm. The display is readable in any light condition including direct sunlight — a significant advantage over LCD displays that wash out.
Battery life is genuinely extraordinary. Running on two standard AA alkaline cells with 2-minute update intervals, the Aranet4 achieves approximately 2 years of continuous operation. This means it can be placed in any room — including locations without power outlets — and forgotten for years. In our 6-month testing period, battery level did not measurably decline.
Bluetooth connectivity to the iOS and Android app provides data logging at the configured interval. The Aranet app displays trend charts, allows export to CSV, and can connect to Aranet Cloud for remote monitoring. The Aranet4's limitation is its sensor set: it does not measure PM2.5. For complete indoor air quality monitoring, pair it with a dedicated PM2.5 monitor. For CO2 specifically — in schools, offices, meeting rooms, bedrooms, or any space where ventilation is the primary concern — the Aranet4 is the correct instrument.
$199 · Precios en USD. Envío desde Amazon.com.
See how the Aranet4 Home stacks up against all 6 models in our full comparison.
Comparación completa →