Coway AP-1512HH and Alen BreatheSmart FLEX are medium-sized air purifiers with high-quality filters and outstanding performance. Coway covers rooms up to 361 sq. ft. It has plenty of Advanced Options from which I would single out the air quality sensor and auto mode. Alen is intended for rooms up to 300 sq. ft. Unfortunately, it can’t boast advanced options such as an air quality sensor or auto mode. I want to emphasize that both devices clear the air 4.8 times in one hour in the rooms of the recommended dimensions. Before moving on to a detailed comparison, I just want

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