Consumer Reports is an independent, non-profit consumer groups that tests the effectiveness of retail products.
Consumer Reports tests a small sampling of air purifiers once every 3 years. Units are picked based on how readily available they are in the marketplace (usually air purifiers sold at big box retailers).
CR tests include how well a unit filters dust, pollen and smoke; the average yearly cost of an air purifier (energy use + filters), and gives each product an overall score.
For more detailed information on Consumer Reports air purifier ratings, click here