Air purification and ventilation are often confused, but they are two different processes that complement rather than replace each other. The difference lies in exactly what happens to the air.
What does ventilation do?
Ventilation refreshes the air in the home: polluted, humid, or CO2-rich indoor air is extracted and replaced with fresh outdoor air. This happens via open windows, vents, or a mechanical ventilation system. Ventilation is essential to do a number of things that an air purifier cannot:
- Lower CO2 levels, which otherwise rise due to breathing.
- Remove moisture, which helps prevent mold growth.
- Completely vent odors and cooking smells outside.
- Supply oxygen from the outside air.
What if you cannot ventilate?
Not every home has windows that can open wide, or perhaps you live on a busy street where opening them lets in extra particulate matter. In those situations, short and targeted ventilation remains necessary for CO2 and moisture, but an air purifier can help in between to keep the indoor air cleaner as long as the windows remain closed.
What does an air purifier do?
An air purifier does something else: it does not bring new air in from outside, but recirculates the air already present in the room by repeatedly passing it through a filter. This removes particles such as particulate matter, pollen, bacteria, and viruses from the air, without CO2 being removed or oxygen being added.
The main difference at a glance
- Ventilation: refreshes the air, removes CO2 and moisture, brings in outdoor air (and sometimes outdoor pollution).
- Air purifier: filters particles from existing indoor air, does not refresh the air itself.
The latter is also a reason why an air purifier can be useful at times when ventilation is less desirable, for example during pollen season, when opening a window also lets pollen inside, or when outdoor air quality is poor due to traffic or urban smog.
Can you measure CO2 yourself?
If you want to know if ventilation is necessary, a simple CO2 meter provides a good practical signal: if the CO2 value in a bedroom or living room rises significantly (above approximately 1000 to 1200 ppm), it is a sign that too little fresh air is being supplied and that ventilation is required, regardless of whether an air purifier is running. An air purifier has no effect on this; only ventilation solves it.
Why it is best to combine them
Ventilation alone does not fully solve particulate matter and pollen problems, especially if the outside air itself is polluted. Using only an air purifier without ever ventilating leaves CO2 and moisture unaddressed, which can lead to a stuffy or humid indoor climate over time. The combination works best: regular short and targeted ventilation for fresh air and a lower CO2 level, supplemented by an air purifier that continuously filters when the windows are closed.
Practical example
Open the windows briefly in the morning and evening to air out the room, and let the air purifier run for the rest of the day and night to continue filtering particulate matter, pollen, and other particles from the air. On the lowest setting, this is also easy to do at night.
Our advice is to see an air purifier as a supplement to, not a replacement for, good ventilation. For the hours when ventilating is not practical, for example during hay fever season or a cold winter day, the Dynter AirPure Plus PA244 with sleep timer and silent night mode is a suitable addition.