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A comment on Ask HN: Indoor air quality sensors and other IoT that's local-first and not DIY?. Parent comment

Re:Ask HN: Indoor air quality sensors and other IoT that's l... by Havoc on Monday November 28, 2022 @03:22PM (#33779001)
Unless I've got another source of VOCs around there should be at least some correlation with actual CO2 levels though? I don't have a reliable way of checking this, but the bottom end seemed well calibrated...outside air leads to a reading consistent with ambient co2
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Re:Ask HN: Indoor air quality sensors and other IoT that's l... by ahaucnx on Monday November 28, 2022 @07:20PM (#33781877)
We tested a lot of VOC sensor modules and the estimated CO2 values they give is -in our experience- 80% of the time totally wrong. Also the absolute ppb values of the TVOC are most often not to be trusted.

What they are good at is detecting spikes, e.g. from cleaning liquids, desinfection etc. but I would not trust the absolute value at all.

The big sensor manufacturers recognized that and newer generations of the Sensirion sensors are now just displaying an "index" instead of absolute measurements.

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