Very efficiently and capably cools a SW facing, approximately 600 square ft room with vaulted ceilings. I am also able to use the cool air that this generates to cool the attached loft with nothing more than the assistance of a Vornado fan. So essentially it cools around 1,000 Sq ft of upstairs high-desert heated un-air-conditioned space impeccably. I really like that the louvre has a mode to go up and down, I feel it helps to cool the space better. Our favorite unit of the four ortabke ac's (all different brands) we own to cool our condo in the summer. Our town has very few homes with central ac, so this is our alternative and it was worth every penny.