I have a large home and have been researching air cleaners for quite some time. I considered BlueAir, IQ air cleaners and several others. What turned me to Alen was 1) Lifetime warranty. Having gone through many air cleaners in the past, this was important. 2) Auto sensor of air quality. Having an air cleaner that could adjust to the air quality was important. 3) Clean a large volume of air. Since it can clean 1100 sq ft on turbo setting, the unit is one of the best on the market. I purchased six BreatheSmart units, placing two of them in an open concept living, dining, kitchen setting, two in the downstairs large family room and one each in each of our two kid's bedrooms. Allergies and asthma are MUCH improved just a few days with the air cleaners.