Newentor CO2 Monitor, Air Quality Monitor Indoor Carbon Dioxide Detector with Voice Alert Large Display, Temperature Humidity Meters, Alarm Clocks for Home, RV, Gyms, Offices, Classrooms , 400-5000ppm

nicer than expected! The picture doesn't do it justice... the display is actually very vivid and pleasing esthetically - which isn't evident from the product's photos. Also note mentioned (perhaps I missed it?) that you can lightly "touch" the upper part (there's sensor there.. not a bottom rather sensor - just gently place your finger there) that toggles between 3 illumination modes - bright, med, and display off. (useful for night time..) Sensitivity wise - seems very accurate, consistant and fast (when on AC power, updates every few seconds). Didn't need to calibrate it as well. It seems accurate out of the box. In the morning when I open all windows wide open, it drops very rapidly to ~400-ish... Seems genuinely responsive to the environment. At night time, without ventilation, it showed around 1500 which is not good. I started ventilation, it dropped to ~800 during the night. You can really get a sense that it's reflecting the actual situation. I can tell the difference when 2 people are sleeping the bedroom vs. one. In short, very nice. Would have been even better if it had WIFI !!! and connected to home assistant. over-all very very nice and useful. Helped me solve my C02 problem. (at first I wasn't ventilating enough, I ramped up the RPM on the inline fan, and it dropped to 800, which is OK, during nighttime).

Most of what you're paying for here is the CO2 meter, and even if that were all this did, it would be good value versus other CO2 meters I've seen on Amazon. It has a big clear display, it can track a high-low range over time, and it can sound an alarm above a customizable level. Dual options for battery and DC power are also welcome. A perk of the battery option is that you'd want to take this outside to recalibrate the CO2 meter (since calibration is based on outdoor levels of CO2). Is it accurate? I don't have more expensive equipment to measure properly, but I do have other consumer-grade meters for temp, humidity and CO2, and this gives very similar measurements. The CO2 measurement is within 50ppm of another meter from a different manufacturer, with the out of the box calibration. It also reacts like you'd expect it to, to things like having more people in the room, or exhaling in its direction. So I have confidence that it isn't just making up numbers, it is actually measuring CO2 levels, and is decently accurate for basic monitoring purposes. As you can tell, I already have a CO2 meter, but what I like here is combining that with temperature, humidity, time, and date readouts, all of which are also useful to have at a glance. I might prefer the clock was more prominently featured on the display, rather than the CO2 measurement (which isn't that dynamic, you either have good ventilation or you don't), but it's all bright, crisp and easily readable.

Thanks to him, I found out that I have very poor ventilation in my house.

This monitor works well. Easy to set up. Uses a high-precision sensor. Comes with a USB cable and also works with batteries. When the USB cable is plugged in, the display stays on continually but can be dimmed or turned off. When unplugged, it reverts to battery power and the display has a timeout. Also displays temperature, humidity, and current time.

product did not fullfil my requierment.may be my mistake also select worng item.