A general overview is presented of the alternative methods of supplying air to conditioned garments. Both compressed air and low-pressure, high-volume air systems are described and many of the aspects involved in the design of the system are discussed, e.g. the types of compressor and fan available, the air-volume requirement, the system pressure drop, pipe sizing and the actual system installation with the particular problems that can arise. The relationship between the air volume and the supply temperature is discussed and a comparison is made between the alternative systems available for air cooling. The vortex tube is described together with the air turbine and comparison is made with conventional vapour-compression equipment. These systems are compared to high-volume systems which could provide large quantities of ambient air at low pressure and cost.