Atmospheric water harvesting (AWH) devices represent a fruitful hope to cope with water shortage problem throughout the world. The vast development in AWH technology and the wide spread of the various AWH techniques will largely contribute in the implementation of AWH machines in different household, agricultural and industrial applications. In the last decades a huge amount of research has been done on AWH methods with amazing differences in results that miss lead the readers and even researchers. In this study the AWH theoretical technology developments, various AWH methods and the various AWH machines in the market are reviewed. A comparison between the different theoretical methods is presented, concentration on unifying results based on area and energy consumption per harvested amount is performed for clear judgment on the different published data. Gaps between theory and market available devices are stated with recommendations for further development in AWH technology.