My husband and I live in El Paso TX where there is a lot of dust and small particles of dead grasses in the air. We tried EcoQuest and other brands of air purifiers/cleaners but couldn't find an answer to the problem (I could dust on one day and dust would coat our furniture by the next day).  Our home is relatively new nevertheless we had somebody look at our duct system to make sure it was clean (and it was), and we resealed our doors, and still dust everywhere.  We tried Winix.  We bought one for the Master Bedroom and when it seemed the air was much better in there we bought another for the living area. We are so pleased with the result.  The dust is much improved, we sneeze less, don't have itchy skin, and note that the Winix systems combined with a humification system improved the quality of the air.  When people come into my home they always say it smells fresh and feels comfortable.  I expect to continue using Winix for as long as we live here.