Review on 🌡️ Humidity Temperature Controller with Efficient Monitoring Function by Allen Hart

Automatic Baseline Calibration (ABC). ABC corrects for sensor drift by assuming the meter sniffs normal air every 7 days. Normal air is 400ppm, so the baseline is adjusted accordingly. I wrote to the company to ask what the calibration would be for the IR sensor drift. I love that this meter comes with the actual full specs including how quickly the sensor responds to changes in CO2 (see PDF on their website): Range: 02000ppm {20019999 (off scale)} Accuracy ± 50ppm ± 5% of the reading ( 02000) Resolution: 1 ppm So if I see 1000 on the display, there are 900-1100 ppm in the air. If there is more than 2000ppm in the air, they simply cannot guarantee a reading. Since the calibration only goes up to 2000ppm, they warn you not to set the high CO2 alarm level above 2000. I like that it has a data port for long term monitoring and a relay port to control external devices. I don't use either, but it's a high-end feature that I could use when building a greenhouse with a CO2 tank to encourage growth. They have high-end devices that are calibrated and accurate over a wider range. It remembers its settings when you turn it off. It would be very difficult to set ABC after a power outage. Use the buttons to scroll through the 15 minute or 8 hour CO2 weighted average and min/max readings. Feels well done. Deep enough to stand alone. I exposed myself to levels of CO2 that would be unacceptable in a California office building.