California's electrical system peak demand is growing rapidly in the residential sector, mainly because of increased air conditioner use due to increased population growth in the central valley. This project compared and evaluated three evaporative cooler technologies that could reduce air conditioning use: conventional, advanced single-stage and advanced two-stage evaporative coolers. Results showed that two-stage advanced evaporative coolers (AEC) deliver air that is 3–4 degrees cooler than a single-stage AEC. Further, this air has less humidity than that of either conventional (“swamp”) or single-stage coolers. Both single- and two-stage AECs use rigid cellulose media, two speed fans, and water management systems to deliver 100% outside air to meet occupant comfort expectations.