Evaporative cooling fans are designed to pull hot, dry air through a water-soaked media filter using a water pump and fan. As the water evaporates into the air, the air's temperature will lower. They are optimal when used in hot, dry climates used to filter ambient air while increasing the condensation and delivering cool airflow. Evaporative cooling fans do not use refrigerants to remove heat like an air conditioner, so they are less effective in high humidity areas. Hessaire MC18M cooling fans are the most versatile portable evaporative cooling fans on the market, delivering 1,300 CFM of cool airflow covering up to 500 sq ft of open space. The MC18M cooling fan has a 4.8-gallon water tank creating up to 3-4 hours of use. The built-in float valve and garden hose adapter allows for easy connection and contiguous water flow without overflowing your tank. This unit has a motor speed dial with 5 settings: 2 fan modes on HI and LOW speed (pump on), 2 fan-only modes HI and LOW speed (pump off). The high efficiency 0.7A motor allows it to operate on vehicles with 115V power supply making it good for tailgating, camping, pool parties and other outdoor events. Assembly is required. Key Operational Points: Your cooling fan must be positioned in front of an open window or door to operate effectively. Always ensure that there is another open window or door through which the air can exhaust from within the room. At the end of each day, run your cooler on FAN ONLY for 30 minutes to dry out the filter. Prior to putting your cooler away for winter, always: a. Drain the tank and wipe out clean. b. Clean the filter c. Reassemble and run-on FAN ONLY for 30 minutes to dry out the filter.