[dallyo]

Well price is no guarantee. Try the hand sanitiser test I detailed above.

[tmoertel]

The CO2 sensor in the View Plus id advertised as follows:

NDIR Sensor (Non-Dispersive Infra-Red): Measurement range 400–5000 ppm Optimum Accuracy ±50ppm ±3% within 10 – 35°C / 50 - 95°F and 0 – 80%RH after initial calibration time

Can you tell from that description whether it's a true CO2 sensor?

[dallyo]

That's proper CO2 sensor then. The cheap ones are estimating CO2 levels from VOC levels.