I never realized how bad the air in my home was until I got the Aranet4. The first time I saw the CO2 levels spike to 1200ppm during a family dinner, it was a wake-up call. Now, I keep it on my desk, and that little e-ink screen is like a silent guardian.

The battery life is insane—I’ve had it for 3 months, and it’s still going strong. No more hunting for outlets like with my old sensor. The app is simple but does the job; I check the graphs every morning like weather forecasts. Though I wish it stored more than 7 days of data.

Traveling with it is a game-changer. On a recent flight, watching the CO2 hit 2000ppm made me understand why I always felt groggy. Now I crack the air vent open—no more mid-flight zombie mode.

Yes, it’s pricey, but after seeing how off my cheaper monitor was (sometimes by 100ppm!), the NDIR sensor feels worth every penny. My only gripe? The Celsius-only display—I still do mental math for Fahrenheit.

This isn’t just a gadget; it’s changed how I breathe. If you’ve ever wondered why you get headaches at work or can’t sleep well, this might have your answer.