Abstract: A misting evaporative cooling system for residential air-conditioner condensers utilizes automatic controls on the misting system to maximize air-conditioner efficiency and minimize wasted water. A low-cost do-it-yourself kit is provided that includes stainless tubing, misting nozzles, tubing support rods, an outdoor thermostat, an electronic water valve, with dimensions suitable for many residential air-conditioner condensers. The outdoor thermostat and indoor air-conditioner thermostat cooperate to control the electronic water valve for maximum air-conditioner efficiency based on variables, such as humidity and ambient temperature, found in locations of use.