- GZAIR CO2 Air Quality Monitor with Data Logger, Wall-Mounted or Tabletop, NDIR Sensor, Temperature & Humidity Tracking, 0–5000 ppm Range (Human/Plant Modes)

I use this CO2 to monitor the level of CO2 gas inside my house. I like the fact that this is a sensitive instrument, measuring the level of CO2 gas in real time. When I'm near the monitor, the level of CO2 goes up as expected, since I'm breathing out CO2 and so raises the concentration of CO2 around the monitor. When the condition outdoors were pleasant, I opened the windows and noticed that the CO2 levels dropped significantly, as expected.It also monitors the current ambient temperature as well as the relative humidity level. The readings of the temperature as well as the humidity level is consistent with another monitor that measures both indoor and outdoor temperature and relative humidity levels.It has a backlight function, which can be activated by touching any of the onscreen function button, which is useful at nigh time or if the lighting is dark.The digits is easy to read and there is also running graph of the monitored CO2 levels for the past several hours. It is powered through the USB port, so it must be connected to a USB charger unit such ones that come with cell phones, which I had plenty of spares.When the monitor powers up for the first time, one might be alarmed by the relatively high levels of CO2 initially indicated. After the monitor has been running for a few minutes, it seems to go through self calibration mode and eventually the displayed CO2 levels drops to the actual measured CO2 levels.

Works great, easy to use and navigate trough the menu. the Log is handy to see what happend overtime (only 7 day's). Display has a good read out and medium size letters/characters.

I live in a van and I am frequently concerned about carbon dioxide levels in such a small enclosed space. I'm always opening windows and ventillating the space when I feel like I'm noticing a low amount of oxygen, but this is all subjective, to the point I feel I've developed some sense of paranoia, that I just needed a factual way of knowing the co2 concentration. So I bought this for that purpose. I wanted to make sure I tested this machine thoroughly before leaving a review. Here are my thoughts:It works very well, if you place it correctly. I would note if you have this item in close proximity with any person in an enclosed space, the readings will be all over the place. The reviews that state the readings aren't stable don't appear to have a good understanding of the physics involved, they just want to put the meter in the most convenient location, like their nightstand, where it won't be so useful. Exhaling carbon dioxide close to a carbon dioxide meter just floods that meter with the co2, and prevents it from being able to obtain an accurate reading of the overall co2 concentration of the entire room. You want to place it as far as you can from the areas you will be or areas that will be affected by air displacement as you walk into rooms, shut doors, etc. "The least disturbed areas" you can think of. This allows the co2 you exhale to have a chance to mix with and circulate into the air of the room, to be able to produce an accurate reading of concentration.Really happy with this machine, as long as you have an understanding of what you're doing and how you might artificially affect the readings, I think you will enjoy this machine too. I would absolutely recommend this to anyone concerned about co2 in their space.

Based on my experience with this, CO2 readings are accurate. Data logging and the menus in general are easy to use and navigate. One big frustration - not having the option of being able to just have the backlight on all the time.

To set this instrument up to operate as you need it you must push a series of buttons in the right order. In reality the "buttons" are simply areas on a screen that is touch-sensitive, or supposed to be. But I never was able to find a way to get them to respond at all reliably to my touch. I tried repeatedly over several days, spending about four hours altogether, before problem lay in the instrument and not my touch. So back it goes.So far as I could tell, the CO2 sensor seems to be fairly reliable and it might be a good instrument if it could be made to work. However, the LCD backlight turns on only when activated with a button push, which may take many tries and may not work at all when it is not in the mood, and turns off very quickly, which would limit the value of the instrument for many purposes.If the controls could be made to work I expect I would have given a three-star rating, assuming that the CO2 values actually proved accurate.

I received an updated unit and I'm very impressed with how it works. The primary monitor for CO2 is fast and I do love the graphing feature that lets me monitor peak over an adjustable time period up to a whole day. This is exactly what I was looking for to monitor peak CO2 in a given room while it's being used. This helps me to adjust airflow through the room when I need it. Both the hygrometer and the thermometer work well enough to make this a single point replacement for multiple meters. Do note that these other sensors are not able to be calibrated (unlike the CO2 sensor) and may have slight errors, but are definitely functional if high levels of accuracy aren't needed here. The touch buttons can be a little clunky, but once you have it setup, you can set it and forget it. For the price and its features I really can't complain

This is a great little device and worth the money. It is calibrated well and was within the expected range both outside and inside when I tested it. The menu and settings are easy to use, and I like that you have the option to turn off the sounding alarm. It’s small and compact. While the price is higher, it’s worth it for all these features and for the accuracy. Would definitely recommend.

Be sure to have a long enough USB 2.0 cable and a dedicated USB cube/power source for wherever you intend to locate the unit. Otherwise, it seems to be a good instrument.