Features:

  • CO2 Range: 0~2000ppm {2001~9999 (out of scale)} / Accuracy ±50ppm ±5%rdg (0~2000) / Resolution: 1ppm
  • With CE Marking, passed the standards and had been approved by European Directives for health & safety
  • Temperature Range: -10.0~60.0°C (14~140°F) /Resolution: 0.1°C/°F / Accuracy: ±0.6°C / ±0.9°F
  • Humidity: Range (0.0~99.9%) / Resolution (0.1%) / Accuracy {±3% (10~90%) **±5% (others)}
  • Perfect to be used to monitor air quality in schools, office buildings, greenhouses, factories, hotels, hospitals and anywhere that high levels of carbon dioxide are generated
Great meter! Turn off Automatic Baseline Calibration if used in a confined area.

If you're using this indoors in an office with closed windows, the manual tells you (page 9) to disable the Automatic Baseline Calibration (ABC). ABC adjusts for sensor drift by assuming the monitor sniffs normal air sometime in every 7-day period. Normal air is 400 ppm so it adjusts the baseline accordingly. I wrote the company to see how big a calibration they would apply for IR sensor drift. I love that this meter includes actual, complete specifications, including how quickly the sensor responds to changes in CO2 (see the PDF on their web site): Range: 0~2000 ppm {2001~9999 (out of scale)} Accuracy ±50 ppm ±5% rdg (0~2000) Resolution: 1 ppm So if I see 1000 on the display, there is 900-1100 ppm in the air. If the air has over 2000 ppm, they're simply not going to be able to guarantee the reading. Since the calibration only goes to 2000 ppm, they warn you not to set the high-CO2 alarm value above 2000. I like that this has the data port for long-term monitoring and a relay port for controlling external equipment. I don't use either, but it's a high-end feature I might if I put up a greenhouse with a CO2 bottle to spur growth. They have higher-end units that are calibrated and accurate over a larger range. It remembers its settings if you power it off. It would be a royal pain to adjust the ABC after any power outage. The buttons let you scroll through 15-minute or 8-hour weighted average readings for CO2 and min/max values. Feels well made. Deep enough to stand on its own. I was subjecting myself to CO2 levels that wouldn't be permissible in a California office building.

and just like the instructions said

Plugged it in as soon as it arrived, and just like the instructions said, after a 30 sec countdown it started to measure my room. Nothing to setup, it works right out of the box. Temperature readout can be set to F as well as C.

Perfect...

we bought 2, and now pay attention well to concentration of O=C=O in our rooms. This helps tremendously. Ventilation ventilation ventilation....

Works well good construction

Exactly as described works great fast delivery

Worked Fine Straight Out of the Box With No Adjustments

I bought this to check whether my building is providing adequate ventilation to my bedroom. It seems to work appropriately. The lowest readings were about 450 after I had been out of the apartment all day, and that is about right for an urban area. After a night of sleeping with the door open, the readings have been about 550, well within the safe range. After a half-hour of rigorous calisthenics it went up to 950 and took several hours to decline below 600. When I breathed on it for about two minutes it went above 1000 and a loud alarm sounded. I used it straight out of the box without reading the small Operation Manual or fiddling with the four buttons that can be used to customize the metrics and defaults. I purchased this unit because AZ Instruments makes a wide range of consumer and professional CO2 meters and thus presumably knows what it is doing, because the few reviews of it on Amazon were very positive, and because two other brands/models that I had considered were reported to emit a blinking light that could be distracting in a darkened room. This unit also has a faint blinking light emitted from the back, but it is only visible at night in my very darkened room when I look directly at the unit. Note: This instrument only runs with A/C electrical power through a provided adapter.

Seems to work OK

No idea if the CO2 meter is accurate, but its numbers make sense (if you leave the window open and leave it drops to like 400, and if you close the windows while inside it goes up to like 800-1000+), and the temp and humidity meters are good.

Gain Express Carbon Dioxide/Temperature/Humidity meter

works perfectly once you have executed the calibration procedure as described in the manual. this is done outside where nowadays the carbon dioxide level hovers around 400 ppm. the entire procedure is automatic after pushing a few buttons and takes only 5 minutes. the audible alarm can be switched off by pushing on any button. the red light warning remains on until a safe level is reached. accuracy is good.

I like knowing the CO2 in the room I am in

This works well. Instructions are hard to understand but with study you can figure it out. I like knowing the CO2 in the room I am in.

Love this thing

Love this thing. Found my little office was going over 2000 ppm with the door closed. The alarm is a great reminder to open the door. The quick updates are also great. You don't have to wait minutes to see it start to drop when you open the window. It refreshes every second.

Follow the manual

Since I started in IAQ as an industrial hygienist, I was looking for something for the home and real time monitoring. So far the device is as accurate as a monthly calibrated 4 gas monitor!

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