ThoroughThe MinusA2 SPA-700A air purifier will filter all of the air in a room up to 700 sq. ft. (or 815 sq. ft. for the SPA-780A) twice in an hour on the high setting. Intelligent Purification, Smart Investment Auto air quality monitoringThe unit will automatically adjust the fan speed based on the air quality sensors. Light sensingA light sensor will automatically transition the unit to sleep mode when the MinusA2 is in a dark room, and resumes a more active mode when light levels increase. ChillWind down with the LED mood light on the front panel, which can be turned on to produce a soothing spectrum of colors, or light your path in the dark. Economical With filters lasting up to two years with 12 hour daily operation, and our Energy Star rated motor, the MinusA2 keeps costs annual costs low. Free Returns At Rabbit Air, we expect our customers to be 100 percent satisfied with our products. Energy EfficientEnergy Star certified units will not run up your energy bill.