Review on 🌬️ CO2Meter RAD 0301 Mini Monitor White: Accurate and Compact Air Quality Detector by Dang Esq

The CO2 monitor is quite light, about the size of a pencil case/pen. Works with any USB micro-B cable connected to a regular phone or tablet charger. Very low power consumption - I've used it on battery power for many days to charge my mobile phone (so I can move the CO2 monitor around different rooms) and the battery level is still at 100%. Of course, as a simple consumer using this at home, I can't tell how accurate this is through empirical testing. But out here in the city it's about 450 parts per million, which seems right considering the average CO2 in the atmosphere is about 400 parts per million. If left in an empty room with the window ajar, it will often show a range of 500-600. As soon as a small room is occupied by a person and a dog or two, the reading jumps to 900-1100. If you open the window further, the number drops back to 700. These changes occur within minutes. So it seems pretty accurate. I like that it has 3 little LEDs, green, yellow, red. Below 800 ppm green. Above 800 yellow. These levels are configured as described in the attached instructions. Involves pressing some buttons on the back. I haven't tried this feature myself. From what I've read about CO2 levels going over 800 or 1000ppm is really undesirable. So "Yellow Alert" seems reasonable to me. The only thing I don't like about this device is that the "yellow alert" also beeps, which is a simple electronic beep. Unfortunately, this repeats itself every 7 seconds. I can not find the function to turn off the sound signal. Drives me insane and eventually I disable the device and violate its purpose. All in all a great price. Pretty cheap compared to industrial CO2 monitors and gets the job done.