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eCO2 and TVOC readings are too high and at limits?

Hardware
#1

Hello,
some weeks ago I got a new SCK2.1 and am very uncertain, why the eCO2 and TVOC readings are so exorbitantly high. I have an older SCK2.1 and put this the days of 28th of March 2023 till 1st of April 2023 right beside each other and the readings are so different. The new one is much after a burn-in time of 48 hours. You can see values of readings here:
New SCK2.1
https://smartcitizen.me/kits/16123

Bildschirmfoto von 2023-04-01 23-08-25
Bildschirmfoto von 2023-04-01 23-08-251447Ă—593 85.7 KB

and here the readings from the older SCK2.1
https://smartcitizen.me/kits/12503

Bildschirmfoto von 2023-04-01 23-08-47
Bildschirmfoto von 2023-04-01 23-08-471450Ă—571 85.8 KB

Hope anyone can give me some help, as I am very disappointed on the differences and unsure what to do.
Best Regards

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#2

Hi @wolfgang, the chip for eCO2 and TVOC is kind of useless pseudorandom generator. Maybe indoor at constant temperature you can find some very weak and uncertain correlation with reality. As it is adaptive, you’ll get different results from the same environment just based on the history. Forget about this part of SCK as it is really useless.
(The huge correlation between eCO2 and TVOC in your “right working SCK” should also tell you, that the values are hard to believe…)

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#3

Hi Marek, I don’t know whether I do understand you right. But will you tell me, that in any SCK the eCO2 and TVOC sensor is not worth looking at, because it is not giving any real readings?
That would mean, that I have to invest in another device to have real measurements of those important indoor air parameters?
In the past, before buying the new SCK, I was trusting the readings of the old
https://smartcitizen.me/kits/12503
as the reading made sense in my invironment, means drinking beer from a tap in the evining increases the CO2 concentration in the night. It was clear for me, that eCO2 and TVOC has a correlation.

#4

@wolfgang you can make your own observations. Pick a random SCK in the map and plot eCO2 and tVOC, you’ll see the corellation. As I said, if there is stable temperature (and maybe also stable humidity and stable tVOC concentration), than the trends of the eCO2 could be right. But for more robust data you’ll need different sensor. As a downside this sensor will need much more power…

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