The use of porous ceramic evaporators for air conditioning was studied. Prototypes, classified as low, medium and high porosity prototypes in direct evaporative cooling mode, were placed in an experimental duct within an environmental chamber. Performance was measured under different conditions of dry bulb temperature (DBT), relative humidity (RH), supply water pressure, and layout within the duct. The high porosity ceramic evaporator consistently performed best, while increased water supply head also improved performance. Dry bulb temperature drops of 6-8 K were achieved parallel with a 30% rise in relative humidity. Maximum cooling of 224 W/m2 was measured during tests on the high porosity ceramic evaporator placed in a single row stack with water supplied at 1.0 m head. Empirical formulae relating mean cooling performance to [es-e], the ambient to saturated vapour pressure difference, were derived. The direct evaporation of water into supply air using porous ceramic surfaces has demonstrated significant potential for air conditioning. 6 refs.