Be aware that the air quality sensor on most units is a cheap VOC sensor. It detects gasses, not particles. It'll trigger if you fart near it or cook something

Be aware that the air quality sensor on most units is a cheap VOC sensor. It detects gasses, not particles. It'll trigger if you fart near it or cook something odorous, but not for dust or smoke. I have the Winix 5300 and 5500 purifiers (which I highly recommend), and typically run on mode 3 out of 4 because it pulls about 12 watts (and is quiet) but is not massively different airflow than mode 4 which draws about 70 watts (and is noisy).