This paper presents a comparison between the measured and predicted performance of different sensible heat storage units. Also, a comparison between the performance of water- and air-based heat storage systems has been conducted. In the air-based systems, natural soil available at Mu'tah site, Jordan, was used as a sensible heat storage material. An experimental set-up was designed for three different storage systems, namely a water storage system, an unstratified air storage system, and a stratified air-based system. The performance of the storage units, i.e. the heat accumulated by the storage material (soil in air storage systems, and water in water storage system) was calculated. A computer program was developed to determine the temperature distribution of the air-based storage systems. The numerical model uses finite difference techniques to solve the governing equations for both the storage material and the circulating fluid. The results showed that the computer model is in good agreement with the experimental results. Also, results showed that the stratified tank performed better than the unstratified one and the water system is superior in storage energy, in spite of its harmful corrosion effects.