Evaporative cooler water use in Phoenix

The authors undertook this study to learn what fraction of total per capita water consumption in growing southwestern Sunbelt cities is made up of water used by residential evaporative coolers. In a field study, water use was metered in sample homes during two cooling seasons. Meters were placed on incoming lines that provided makeup water to the evaporative cooler reservoir. Monitoring devices were configured to capture and meter the bleedoff water so water consumption for evaporation could be separated from total water delivered to the cooler. Average annual household use of water for all homes was 108,382 gal (410,271 L). Water used by each household for cooler operation, regardless of the kind of cooler system, averaged 66 gpd (250 L/d)—15 percent of total household water use—during the 214-day cooling season. Homes with a bleedoff system on the cooler used an average of nearly 50 percent more total water for cooler operation than did homes with no bleedoff system.