We initially purchased one of the smaller Cuisinart air purifier units to use on a countertop in the kitchen to help mitigate cooking smells.  It worked so well, we started moving it to our bedroom at night to see if it might help with allergy issues.  It helped so much that we purchased a 2nd unit for that room and this larger unit for our 
 living room/dining room area.   Runs very quietly.   Would recommend.