The Puritii APS will clean a 920 square foot room every half hour. However, the Puritii APS, like all standalone air cleaners, depends on air circulation to have the greatest effect. Compact air cleaners are not very good at circulating the air behind walls and closed doors, down hallways, or on different floors. Therefore, we recommend taking advantage of the portability of the Puritii APS and moving the unit to where you are! For example, put the APS in the main living area during the day and move it to your bedroom when you sleep. You could also purchase another unit to more efficiently clean and maintain pure air in separate areas of your home.