An air conditioned space is cooled within a narrow target zone (as depicted on a psychrometric type chart) within which human occupants of the conditioned space would feel thermally comfortable, wherein factors including the heat transfer resistance of occupants' clothing and level of physical activity determine the target zone, by a method which includes correction of operative temperature, relative air velocity and humidity within the conditioned space 104, inherently controlling humidity by control of effective dehumidifier size 102 while maintaining a low face velocity of air and a high velocity of coolant flow, but varying either, or both, dehumidifier size 102 and the leaving air temperature if humidity ratio falls below four or exceeds thirteen grams of water per kilogram of dry air.