Summary and product recommendation
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An air purifier for asthma relief must be capable of trapping small particles such as pollen, pet dander, pollution and dust and be powerful enough to drag all of the air in the room through the filter a minimum of 5 times an hour (ACH) for it to be genuinely effective. To get around 5 air changes per hour in your room measuring between 26 and 30 m2 you need an air purifier with a clean air delivery rate (CADR) in the range of 400-499 m3/h. CADR rating indicates how fast an air purifier can clean the air within a particular size room. It provides a way to compare air purifiers taking into account both airflow and a filter's efficiency.
Most common allergens like pollen, mould spores, pet dander and dust mite faeces range from about 100 microns down to around 0.3 microns.
True HEPA (H13) or medical-grade True HEPA (H14) air purifiers are excellent for those with asthma as they capture minute pathogens. A True HEPA H13 filter can capture up to 99.97% of airborne particles greater than 0.3 microns. A True HEPA H14 filter is 10x time more efficient as it captures particles as small as 0.1 microns.
For a bedroom or baby room, you may want to use a quieter air purifier that comes with "night" mode. Air purifiers with "night" mode run quietly in the background allowing you to enjoy clean air while you sleep.
This tool is for guidance only and does not replace professional advice on product selection.