CO2 Detector, 10-Years Battery Life Indoor Air Quality CO2 Monitor Carbon Dioxide Monitor NDIR Sensor 400-5000 PPM, 1600 mAh USB Rechargeable CO2 Alarm Meter for Home, Office, Car, Gym

Simple instructions included in box. Easy to calibrate and use. Very useful to check air quality within the home. We have a Victorian home with sash windows... the CO2 is lower in these rooms than in the modern kitchen with tightly sealed double glazed doors and windows. In the kitchen the air is in the red zone 😣🤕I'm going to take this to work and test our stagnant air-conditioned workspaces. Then make a report for the management. I'm sure the readings will be horribly high!

I’ve bought this to use in my van to keep a watch on my air quality

Das Display ist sehr gut. Was noch fehlt ist eine Funkuhr und eine Außentemperatur Messung. Und es könnte noch größer sen.. Ansonsten ist das Teil sehr, sehr gutIch habe schon mehrere davon..jetzt weiss ich zum Beispiel wann ich lüften muss usw. Klare Empfehlung von mir...

I have only had this AQM for a day, so a fairly limited review for now. It seems to be accurate (although I have no means to test the CO2/PM2.5) for temp & humidity, so no reason to think the other sensors would be any different. For sure, if you stand near it it reacts to breath exhalations in its general vicinity !These is obviously a fan internal to the monitor - it can be heard but it is not too intrusive. It might bother very light sleepers but I had no problems with it last night. LED display can be dimmed for nighttime use, but it would be better if this were automatic.All in all, I am happy with this purchase and will report back in due course.K

This is a nice easy to use CO2 meter that displays the CO2 level in parts per million (ppm). The clear and bright display shows values from 400 to 5000ppm. It also shows the temperature and the humidity, but these values are not always representative of the surrounding air (for reasons explained below). The meter is precise (it's display increases in units of 1ppm, with no apparent dropouts) and CO2 readings appear reasonably reproduceable. Hopefully it's accurate too. There are pros and cons, but the pros outweigh the cons and so I'd rate the product as 9 out of 10, and think the product deserves 5 stars rather than 4. When left outside in my garden in Loughton, next to Epping Forest, I get values which hover between 413ppm to 416ppm, or between 415ppm to 418ppm on another day. These are well accepted values for this area, hence my belief in its accuracy. Breathing, just once over the back of the monitor (where the air enters) will cause it to max-out at 5000ppm (after about 20 seconds), presumable as the air needs to diffuse into the sensor. It will recover its value after about 60 seconds, depending on the air flow (waving it about or putting it in the air flow of a fan speeds up it's recovery). It sounds an alarm at a pre-settable level from 800ppm to 2000ppm. This can be annoying in a cosy (hence not very well ventilated) room. The alarm can, however, be turned off by pressing, and holding button (3) (the UP button), contrary to (the single click of button (1) printed in) the instructions. When charging (at about 557mA from a USB outlet) the battery icon will be red, but once fully charged goes green. When not charging it runs on its internal, non-replaceable, batteries the battery icon is also green, but goes amber when the battery gets low and then shuts down automatically when depleted. The brightness of the display can take about 7 different values using the UP and DOWN buttons (2 and 3 in the instructions). The dimmest can still be bright (when in the bedroom with the lights off - I find a couple of post-it notes attached over the screen provide the correct additional reduction in intensity for me), although the higher settings are best when viewed outside in the sunshine. Unfortunately, at maximum brightness considerable warming of the display panel occurs. This results in the temperature being displayed being up to 4 degC too high. The humidity shown changes drastically with the display temperature. For example, at minimum brightness 18 degC and 70 %RH is shown when the room temperature is about 18 degC, however, just by setting maximum brightness theses values will change, the temperature going up to 21 degC and the humidity goes down to 46 %RH. For this reason I'd only rely on the temperature to be accurate at minimum brightness. Clearly a humidity value ranging from 70% to 46% just by changing display brightness shows how unreliable the value is (however I find a massive discrepancy between all my (electronic) humidity meters). The display brightness does not however appear to have any negative effect on the CO2 value displayed. The CO2 levels act as a proxy for air quality because (as shown above) outside air is about 420ppm. The air we breath out is about 38,000 ppm. Hence the percentage of re-breathed air is given (roughly) by (actual CO2 reading - 420) / 38,000 x 100%. That means that each 380ppm above 420 is another 1% re-breathed air. So 800ppm reading is 1%, 1200ppm about 2%, 1600ppm about 3%, etc. The meter also has a green/amber/red scale (above 1000ppm goes amber, above 2000 goes red). The shockingly high CO2 values I'm observing at home are a real wake-up call to proper ventilation.In spite of its flaws I think this is a great product, well worth the money, and I'd recommend anyone to get one too.