Where Should I Put a CO2 Monitor in a Large Room?
Ideally a monitor should be positioned towards the centre of the room, around breathing height (1.5 m) or a little higher. Avoid placing it very close to people, as their direct exhaled breath (with ~40000 ppm CO2) could perturb the measurement. Also avoid placing them next to windows or HVAC supply vents where air is coming into the room. Placing them next to HVAC exhaust vents can be useful, since these sample the average air of the room.
You can also experiment by moving the CO2 meter to different locations in the room. Typically differences are small in most well-occupied rooms, once the steady state level has been reached.
You can check out more information on CO2 monitors via this link: https://airspothealth.com/a/blog/category/co2-monitors
