Abstract Plant production in greenhouses in hot and dry climates needs sufficient cooling for optimal production. Conventional pad and fan cooling systems require desalinated water which limits their application. Furthermore, the horizontal ventilation causes undesirable temperature and humidity gradients in the cropped area. To overcome these disadvantages a new air-conditioning system was developed and tested in Greece and Kuwait. This system consists of an air washer, an air distribution unit, a movable thermal screen and an electronic controller. The air washer can be operated with low quality water. Effective cooling, cleaning of the inlet air and uniform temperature and humidity distribution are also points in its favour.