we bought the blue air model 121 from these folks, and we really love the unit! it clears the air in our 2 story, open beam ceiling, 1550sq ft house very well. it got a good test with the fires raging in california this year, and the resultant very poor air quality due to smoke. it could clear the air on high, and then run on low to maintain the clean air. on low, it is very quiet. we loved ours so much, we ended up helping 3 other people get a unit as well. there was a snag in the order/delivery process due to high demand and low availability, but rex and team resolved it very fairly- really the best customer service one could hope for!