Template
Use CO2 trends to test ventilation changes in the room you actually work in
The trend after the change is often more useful than arguing about one isolated number.
When it fits
- The room feels stuffy and you want a simple way to see whether an airflow change has an effect.
When to avoid it
- Do not open windows when outdoor air, weather, security or noise makes that unsafe; CO2 does not measure every pollutant.
A template to use
Occupants: [count]. Baseline CO2 trend: [trend]. Ventilation change: [change]. New trend: [trend after]. Comfort/other constraints: [notes].
Why it matters
A consumer CO2 monitor can support a bounded ventilation experiment: observe the occupied-room baseline, change window/door/ventilation conditions safely, then watch whether the trajectory changes. Record occupancy because people themselves are a major indoor CO2 source.
An example
Compare a closed-door work block with the same room after opening the door and enabling mechanical ventilation.
Check your result
The monitor is used to learn how the room ventilates under real occupancy rather than to chase a universal magic number.
Keep this limit in mind
- Do not open windows when outdoor air, weather, security or noise makes that unsafe; CO2 does not measure every pollutant.
Evidence and sources
ASHRAE supports meaningful indoor CO2 monitoring when measurements are interpreted in the context of occupancy, ventilation and the built environment.
Do not open windows when outdoor air, weather, security or noise makes that unsafe; CO2 does not measure every pollutant.
ASHRAE Position Document on Indoor Carbon Dioxide · See source record