I thought I was buying an evaporative cooler but its more like a humidifier. It has a filter that you can wet and freeze but it doesn't hold the water very well. The main source of water comes from a small part inside the cooler that sprays a fine mist. The mist doesn't seem to make a difference to cooling as it only lets a small amount of water out at a time. A true evaporative cooler 2ould be much more effective. That being said it still a fan and it will do for now.