Hydrofarm APCEM2 Data Logger Autopilot Desktop CO2 Monitor, White/Blue

There is no backlit display as the picture shows. Also it's not a true data logger, you can't download data it stores for the display. The USB port is just for power. Also there is no internal battery so it won't work unless it's plugged in.This is an interesting and useful instrument that does not live up to it's potential. Disappointing.

This is a long term review as this was bought April 2017 ! I use this weekly, almost daily.I wanted a co2 monitor for two reasons to tweak my co2 production in my greenhouse to optimal levels and to have indoors especially in winter to monitor co2 levels. I didn't want to spend many $100's on a large commercial monitor but I still demanded quality and accuracy.In winter the air becomes stale since windows are shut and that outside - inside air movement slows. We can easily find indoor co2 levels much, much higher than outdoors. This is especially true in bedrooms, enough so that people can actually come down with headaches as well as other symptoms. So this is why I do check the house from time to time in winter.For my greenhouse I use this to keep co2 at appropriate levels for what I'm currently growing. Bedding plants, some veggies, orchid and common houseplants I find that this monitor gives a nice real-time reading so I can adjust my co2 output quite easily.I would have considered this to be 110% perfect if it did have that backlit lcd screen as the listing picture does show. It still is quite visible as is but that would be on my wish list. I would also have liked this monitor to have at least 9V battery capable. As this is currently engineered, a USB cable is needed to power on this unit. Not a huge deal as we don't have to worry about a battery going dead but having that battery would add to this devices portability.I knew this does not communicate with a computer to download the data, that feature was not that important to me as the monitor itself holds this information which suits my needs.TIP ► To test to see how this works for you, easy peasy. Put this outdoors for a few minutes and see the reading it gives. The outdoor air is a KNOWN value so we can test against this. Right now the atmosphere is in that 413-414ppm level and this can be checked against many online sources. For myself I simply put this outside, wait and in this case took a picture to show everyone here my own monitor. At this point it gave me a reading of 411ppm. That is pretty darn accurate in my books. Therefore I can trust this monitor to give me accurate readings.For anyone who wants an ACCURATE co2 monitor, this is for you !Helpful, is how I hope you find my review

The backlight issue that has been mentioned: It doesn't show a backlight normally, but when one pushes one of the buttons, it lights up for a minute or so in order to view the display better. (Still, one has to find and click a particular one of the small film buttons that won't change a setting when you do click it).I'm using the gadget for CO2 monitoring in rooms in a house without a heat recovery ventilator or air ducts -- so a small office or bedroom can get stuffy.Great to have the plot to see trends over the last hours or day (or whatever time interval you set it to). Not having a downloadable log, and losing data when unplugged, will be a problem for some people. (At least one can hook the USB cable up to one's own USB battery pack if one wants to move it around without data loss.)

I am glad I bought this CO2 monitor. It shows me air quality in a room. The monitor is quick and can determine air quality after one minute on. There is a graph that shows you a reading of temperature in the air. Over a minimum of one minute time period. You can set the CO2 monitor for humans or plants. Comes with a wall plugin and has no compartment for batteries. Has no backlighting for night viewing. There are however a single lite light to let you know you are on target - (low is a red light, Target green, and high is yellow. I would recommend this monitor to anyone looking for a good CO2 monitor. There is a variation of accuracy of 70 parts per million (PPM) plus or minus.

is anybody else having problems with the accuracy of the readings? the RH is showing 10% less than my other meters as well as 2 degrees centigrade higher. This kind of makes me question how accurate the co2 ppm readings are. theres been a very large swing in the data sets. fluctuations as much as 1000ppm with no environment changes whatsoever. i'll give it a few more days of testing but I'm seriously considering returning it.