I use a Sensirion CO2 sensor for automatic home ventilation. It works well, because ventilation is more about the relative levels of CO2 and rate of change. I'm

I use a Sensirion CO2 sensor for automatic home ventilation. It works well, because ventilation is more about the relative levels of CO2 and rate of change. I'm not sure the exact value as reported by the sensor is very accurate. TVOC sensors are indeed useless. They measure so much noise that you can't use the data for anything.