Bests & Worsts Reviews from Amazon

Right out of the box, this unit works. The Co2 and VOC level are right on par with my professional indoor lab tests. That is until... 1) the first time you cook 2) the first time you leave the windows open in the house 3) spray any kind of chemical it can detect even from a far distance. These sensors start off correct but gradually lean towards the extreme. Meaning, your voc and co2 (especially voc) will never get back to the original calculation once its been effected by any variable. Lets say VOCs were at 120 to start. You cooked one day and level went to 500. After you air the house out, new default is 150. It never goes back to 120 no matter what. Then you leave the windows open on a warm day and watch VOCs drop to 20 (as low as it measures). Hour later, now its at 180 and 180 becomes your new baseline. It just gradually grows forever after each time it is effected by a variable. The lady at tech support was super nice and remote calibrated it.... did nothing to solve the problem. Leave it outside to air out.... no change. I went through 3 of these. Thats right, 3. Bought 1, returned it Bought 2nd, then swapped that for a 3rd. Still using the 3rd to somewhat manage CO2 at night, but thats about all its good for. My theory is that the sensor is super cheap and becomes damaged or uncalibrated by basically anything. Theres soooooo much junk on the market, I cant suggest something better in the consumer price range. But these were my frustrations with the product. After using 3 of these... I can safely say that there is no fixing this. Buy it if you need good readings for a few days. If you need it to work beyond that.... good luck to you