CPCSupport:Cheap CO2 Monitors

DRAFT

20+ years ago, if you wanted a portable NDIR CO2 monitor that you didn't have to lug around, you had to go to a company like TSI/Alnor Instruments, and potentially shell out thousands for a CompuFlow, Q-Check, or IAQ-Calc. Later, cheaper sensors started emerging, and were incorporated into newer instruments sold by companies like TSI, with maybe some more competitors driving the price down, but they were super niche and uncommon outside of industry.

The solution in the past would've be to say: screw it, let's just estimate CO2 using some other, cheaper sensor. Or forgo measuring CO2 in our buildings altogether. But thanks to sensor competition in the late 2010s by companies like Sensirion, the cost of actually-usable CO2 sensors has come way down, but still cost hundreds of dollars, right? You may be surprised. Here, I'll review three different ways of measuring CO2 reliably and cheaply.

Bear in mind that this is not an invitation to stop wearing your respirator because the CO2 has dropped below 1000 ppm. Whatever device you choose is going to be mostly informational, since SARS is exceptionally durable now, sometime even out of doors. It is useful for discovering how contaminated a room might after everyone has left, since reports indicate that the inactivation of SARS in a 3000 PPM+ environment may plateau, potentially putting you at risk even when an empty room should be ostensibly safe.