The quality of the air we breathe every day is not always perceptible. However, one parameter can help us understand when air exchange in an occupied space may not be sufficient: the concentration of carbon dioxide, or CO₂.
CO₂ is produced primarily by human respiration. In an enclosed and occupied space, its concentration tends to increase when the air exchange rate is not adequate for the number of people present and the characteristics of the room.
For this reason, measuring CO₂ can be useful for assessing how ventilation is being managed, for example in bedrooms, offices, and meeting rooms.
But there is an important point to keep in mind: CO₂ does not tell the whole story. A low CO₂ level alone does not guarantee that the air is free from dust, volatile organic compounds, or other contaminants. Likewise, CO₂ concentration is also influenced by occupancy levels and outdoor conditions.
What role does MVHR play?
A mechanical ventilation with heat recovery (MVHR) system promotes air exchange through airflow rates defined and managed according to the system design. When correctly sized and adjusted, it can help limit CO₂ accumulation in occupied spaces.
Sensors can also support demand-controlled ventilation by adjusting airflow according to the conditions detected, when the system is designed to operate in this way.
The key takeaway: CO₂ is a useful indicator for understanding air exchange, but it is not a universal measure of indoor air quality.
