Review on Supco IAQ50 CO2 Carbon Dioxide Meter Indoor Air Quality Monitor with Temperature, Humidity, Dew Point, and Wet Bulb - Desktop or Wall Mount by Rich Rickenbaugh

I bought this unit because I installed an unvented gas heater in my basement to heat my office. The CO2 meter came a few days before the plumber came to connect the heater, so I connected it to get an idea of the baseline CO2 levels without this new heater. Of course, humans exhale carbon dioxide. The meter is about 5 feet from my body at 9 o'clock when I'm at my desk at 12 o'clock. When I sat down, the counter read 451 parts per million. After about an hour it showed 568ppm just because of my breath. When two plumbers were here to hook up the heater to the gas line, the three of us were within 10 feet of the meter. The reading at the start was 465. The reading with three breaths for an hour was 760. I don't know how accurate that is, but it's definitely sensitive. Easy to use. The alarm can be set to different CO2 values. A little pricey compared to carbon monoxide meters but well worth the money with a non-vented gas heater 6ft behind me. By the way, the carbon monoxide (CO) meter is at 3 o'clock when I look at 12 o'clock. CO2 on my left and CO on my right. One cannot be overly cautious with non-vented combustion heaters in my opinion.